Stain removal

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Stain removal is the process of removing a mark or spot left by one substance on a specific surface like a fabric. A solvent or detergent is generally used to conduct stain removal and many of these are available over the counter.

Contents

Stain prevention

If a stain has "set", it has become chemically bonded to the material that it has stained and cannot be removed without damaging the material itself. It is therefore important to avoid setting stains that one wants to remove. This can be done by avoiding heat (by not pressing or ironing the stain), sponging stained materials as quickly as possible, using the correct solvent (some solvents will act as catalysts on certain substances and cause the stain to set more quickly), and avoiding rubbing the stain. [1]

Stain removal is possible due to hydrophilic end and hydrophobic end present in detergents. The hydrophilic end of the detergent attaches itself to the water molecules while the hydrophobic end attaches itself to the material and the molecules of the stain. The hydrophilic end allows for the stain molecules to be water soluble. [2] [ clarification needed ]

Stain removal

Most stains are removed by dissolving them with a solvent. The solvent to use is dependent on two factors: the agent that is causing the stain, and the material that has been stained. Different solvents will dissolve different stains, and the application of some solvents is limited by the fact that they not only dissolve the stain, but also dissolve the material that is stained as well. [1]

Another factor in stain removal is the fact that stains can sometimes comprise two separate staining agents, which require separate forms of removal. A machine oil stain could also contain traces of metal, for example. [1] Also of concern is the color of the material that is stained. Some stain removal agents will not only dissolve the stain, but will dissolve the dye that is used to color the material.

Solvents

These are some of the solvents that can be used for stains, with some examples of the stains that they are capable of removing: [3] [4]

Oxidizing solvents

Household bleach generally removes a stain's colour, without dissolving the stain itself. Hydrogen peroxide is also a bleaching agent that can be used to treat stains. [3] Sodium perchlorate is a bleach alternative.

Reducing solvents

Sodium hydrosulphite and sodium hypochlorite normally used for removing stain and dyes colors.

Lacquer solvents

Acetone is good for removing some glues, nail polish, ink stains, rubber cement, and grease. Nail polish remover may contain acetone, however for general use it is best to obtain bottled acetone from a hardware store. It can be diluted with water. [3] [4]

Inert solvents

Inert solvents are those that do not react with anything in the stain. Water for example can be considered as an inert solvent for some kinds of stains. In this case dissolving the stain is not a chemical reaction but a physical process.

Detergents

Surfactants (detergents) are molecules that have one polar end and one non-polar end and can be used for stain removal. They can help to emulsify compounds that are not usually soluble in water. For example, if you put oil in water, they tend to stay separated. If you put oil, detergent, and water together and shake them up, then you get a mixture that can help to remove stains.

Acids

Lemon juice, containing citric acid which is the active bleaching agent, can effectively remove stains. Its action can be accelerated by exposing the stain to sunlight, or some other UV source, while soaking. [3] Various acids were used in the past such as Phosphoric acid as used in Calcium Lime Rust Remover (CLR) and Hydrofluoric acid as used in the Australian product made in Queensland called "Rustiban". Both of these Acids have been removed from sale to the general public due to toxicity concerns. Both of these acids were used primarily to remove rust. Other rust removal acids are oxalic acid.

Oxalic acid, also called ethanedioic acid, belongs to the carboxylic acid family. Oxalic acid is used widely as an acid rinse in the laundry industry due to its ability to remove rust and ink stains. Oxalic acid converts insoluble iron compounds into a soluble complex ion. It is because of this property that oxalic acid is one of the primary components in commercial solutions used to remove scale from automobile radiators. [5] See also Borax or Boric Acid, Vinegar ( or acetic acid ) which can also help bring out stains.

Alkalis

Alkaline stain removers are mostly used in the removal of oil-based stains via the process of saponification. [6] Sodium Hydroxide is also commonly used in drain cleaners. It allows grease and other oils to dissolve into aqueous solutions like water. Other alkalis such as Potassium Hydroxide (much stronger than Sodium Hydroxide) are also used. Both of these are hazardous chemicals and react with animal flesh. High enough concentrations, as in industrial cleaners, and/or significant exposure time without adequate protection of the exposed area will cause serious chemical burns. Alkalis helps remove dirt, grass, and clay stains. See also Cloudy Ammonia / Ammonia

Enzymes

Enzymes are used in "bio" laundry detergents to digest protein-based stains like chlorophyll-linked proteins in grass stains and hemoglobin-linked proteins in blood stains. One of the most intensively studied protease for this purpose is subtilisin.

Others

Baby powder
This can be used to absorb grease before washing, especially for fresh stains. [7]
Club soda
This can be used for pet stains and out of doors. [3] There is no chief underlying chemical reason why club soda would be superior to plain water in stain removal. [8]
Glycerine
This can be used to soften "set" stains, especially on wool and non-water-washable fabrics. [3]
Boiling water
This can be used to take out fruit juice stains. Hot water activates the detergent and as well as sanitize the cloth. It works best on protein-based stains. [9]
Lukewarm water
Water is an excellent solvent for colorless sugary stains, such as sticky residues of dropped candy as well as apple jam and honey.[ citation needed ]

Application of solvents

There are four ways to apply a solvent to a fabric for removing stains: [1]

Soaking

This is a common method used in households to remove a variety of stains. Depending on the stains composition, the stained material is left to soak in a container of warm or cool water and solvent. Such solvents can include laundry detergent, bleach, peroxide, vinegar, or a cleaning product with enzymes. Soaking in the water-solvent mixture allows for the stain to be loosened from the fabric, thus making it easier to remove with scrubbing or washing. [10]

Application of Pressure
Sometimes called tamping, this method involves pressing the solvent into the stain. The pressure allows for the solvent to better penetrate both the material as well as the stain. This technique is commonly used on durable woven fabrics, as less durable material may be damaged. In this method a soft bristled brush is used to directly press the solvent onto the stain. When using this method it is important to not use too much pressure, so as to avoid damaging the stained material. [11]
Front Sponging
This is the most common way of treating non-washable fabrics. The front of the fabric is sponged with a sponge that is soaked in the solvent being used. The rear of the fabric should be backed up with a clean, absorbent, material. The stain is rubbed with the sponge radially, from the centre of the stain towards its edge. It is important not to rub the sponge in a circular motion, as that causes the stain to spread in rings. [1]
Back Sponging
The stained side of the material is placed face down on a clean, absorbent, material. The back of the fabric is then sponged with a sponge that is soaked in the solvent being used. It is important not to rub the material with the sponge, but to use a padding motion, so as not to spread the stain. The solvent dissolves the stain, which is deposited on the absorbent material beneath. To completely remove the stain it may be necessary to use more than one absorbent pad. [1]

Hair dye stains

Hair coloring products are commonly used in both households and salons. Due to the length of time that hair dye must be on the hair to achieve deep, even results, it often seeps or drips down onto the hairline, ears or neck, causing unsightly and irritating stains on the skin. Dye users are not universally affected, most likely due to the variations in lipid or natural oil composition on the skin surface from one person to the next. [12]

Many salons and stylists advocate the use of petroleum jelly to prevent stains. Placing a rim of petroleum jelly around the hairline creates a physical barrier to prevent the dye from running down onto the skin of the forehead and neck, and fills the pits and recesses within the epidermal layer.

Chemistry

Human hair is composed largely of keratin protein, which has a negative ionic charge, giving hair a negative ionic charge as well. [13] As chemistry dictates, oppositely charged compounds attract and compounds with the same charge repel each other. Most hair dyes are positively charged, helping them attach to the negative sites in hair and contributing to a better bond between the dye and the hair.

Unfortunately, like hair, human skin is made of keratin and contains sites with a negative charge, and therefore, it also attracts the dye. Skin also has pores and other pits and recesses which allow dye to get physically trapped in the epidermal layer. These both contribute to the development of stains on the skin.

The dye itself can be directly absorbed through the skin and into the bloodstream. [14] The stratum corneum (the outermost layer of skin also called the “horny layer”) contains a “lipid domain” that allows the dye to pool and provide opportunity to diffuse into the body. [14] Some hair dyes can also irritate the skin with prolonged exposures. As a result, quickly removing or minimizing skin exposure to dye is often considered desirable.

Removal methods

While many home remedies exist to attempt to remove the stains from skin, there are many products distributed in traditional drugstore or discount channels for this purpose. The home remedies vary in effectiveness and carry the risk of skin irritation and abrasion as a result of excessive scrubbing, plus eye irritation if allowed to drip or run into the eye. Some of the more common home remedies include: bleach, ammonia, acetone, and rubbing alcohol.

The following are risks of the common removal methods:

Acetone
The CDC reports that repeated and prolonged exposure of the eyes to acetone has the potential to cause permanent vision problems resulting from corneal clouding. [15]
Ammonia
Ammonia is also contained in many hair dyes. [16] Hair colors containing ammonia have been safely used for years. However, ammonia exposure can cause conjunctiva irritation of the eyes. [17]
Bleach
Traditional bleach contains chlorine and/or hydroquinone. Chlorine can irritate and burn skin, as can skin-bleaching products [ citation needed ].
In the United States, the FDA has proposed a ruling to remove all skin bleaching products from being available over the counter. [ citation needed ]
Isopropyl Alcohol
Concentrated isopropyl alcohol has been shown to irritate skin, and prolonged inhalation of the vapors can impair coordination and cause headaches. [18] While it may be an effective stain remover, it must be used gently to avoid abrasion of skin.

See also

Scientific American , "Removal of Stains and Spots", 20 November 1880, p. 329 (historical perspective)

Related Research Articles

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A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules, and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell.

<span class="mw-page-title-main">Petrochemical</span> Chemical product derived from petroleum

Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.

<span class="mw-page-title-main">Dry cleaning</span> Cleaning of fabrics in non-aqueous solvents

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<span class="mw-page-title-main">Sodium hypochlorite</span> Chemical compound (known in solution as bleach)

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<span class="mw-page-title-main">Cellulose acetate</span> Organic compounds which are acetate esters of cellulose

In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, and as a frame material for eyeglasses; it is also used as a synthetic fiber in the manufacture of cigarette filters and playing cards. In photographic film, cellulose acetate film replaced nitrate film in the 1950s, being far less flammable and cheaper to produce.

<span class="mw-page-title-main">Wood stain</span> Type of paint used to colour wood

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<span class="mw-page-title-main">Household chemicals</span>

Household chemicals are non-food chemicals that are commonly found and used in and around the average household. They are a type of consumer goods, designed particularly to assist cleaning, house and yard maintenance, cooking, pest control and general hygiene purposes, often stored in the kitchen or garage.

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<span class="mw-page-title-main">Carpet cleaning</span> Process of removing dirt and stains from carpets

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<span class="mw-page-title-main">Bleach</span> Chemicals used to whiten or disinfect

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<span class="mw-page-title-main">Cleaning agent</span> Substance used to remove dirt or other contaminants

Cleaning agents or hard-surface cleaners are substances used to remove dirt, including dust, stains, foul odors, and clutter on surfaces. Purposes of cleaning agents include health, beauty, removing offensive odors, and avoiding the spread of dirt and contaminants to oneself and others. Some cleaning agents can kill bacteria and clean at the same time. Others, called degreasers, contain organic solvents to help dissolve oils and fats.

<span class="mw-page-title-main">Finishing (textiles)</span> Manufacturing process

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<span class="mw-page-title-main">Conservation and restoration of ceramic objects</span> Preservation of heritage collections

Conservation and restoration of ceramic objects is a process dedicated to the preservation and protection of objects of historical and personal value made from ceramic. Typically, this activity of conservation-restoration is undertaken by a conservator-restorer, especially when dealing with an object of cultural heritage. Ceramics are created from a production of coatings of inorganic, nonmetallic materials using heating and cooling to create a glaze. These coatings are often permanent and sustainable for utilitarian and decorative purposes. The cleaning, handling, storage, and in general treatment of ceramics is consistent with that of glass because they are made of similar oxygen-rich components, such as silicates. In conservation ceramics are broken down into three groups: unfired clay, earthenware or terracotta, and stoneware and porcelain.

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<span class="mw-page-title-main">Hard soap</span>

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The conservation and restoration of leather objects is the process of determining the causes of deterioration, followed by deciding the best course of action for preserving the leather objects for the future.

<span class="mw-page-title-main">Detergent enzymes</span> Biological enzymes that are used as laundry detergents

Detergent enzymes are biological enzymes that are used with detergents. They catalyze the reaction between stains and the water solution, thus aiding stain removal and improving efficiency. Laundry detergent enzymes are the largest application of industrial enzymes.

<span class="mw-page-title-main">Fabric treatment</span>

Fabric treatments are processes that make fabric softer, or water resistant, or enhance dye penetration after they are woven. Fabric treatments get applied when the textile itself cannot add other properties. Treatments include, scrim, foam lamination, fabric protector or stain repellent, anti microbial and flame retardant.

References

  1. 1 2 3 4 5 6 "How to remove stains from almost anything". Popular Mechanics. Hearst Magazines. October 1973. pp. 96–99.
  2. ↑ "Soap and detergent | Chemistry, Uses, Properties, & Facts | Britannica". www.britannica.com. Retrieved 2023-01-29.
  3. 1 2 3 4 5 6 Georgene Muller Lockwood (2002). The Complete Idiot's Guide to Organizing Your Life. Alpha Books. pp. 176–177. ISBN   9780028643182.
  4. 1 2 Jeff Bredenberg (2000). Clean It Fast, Clean It Right. Rodale. p. 491. ISBN   9781579540197.
  5. ↑ "Oxalic acid | Formula, Uses, & Facts | Britannica". www.britannica.com. Retrieved 2023-02-03.
  6. ↑ Esha (2023-07-28). "The Science of Stain Removal: Alkaline vs Acidic Cleaners". ORAPI Asia. Retrieved 2024-09-05.
  7. ↑ Tyler, Gemma. "The Ultimate Coffee Stain Removal Guide – (Homemade Natural Hacks)" . Retrieved 10 June 2020.
  8. ↑ Wishnok, Pete. "How does club soda remove red wine stains?". Scientific American. Retrieved 15 April 2016.
  9. ↑ "Coffee Stain Removal 2021 Guide (UPDATED) – (Natural Hacks)" . Retrieved 23 Jan 2021.
  10. ↑ "Stain Removal Guide | The American Cleaning Institute (ACI)". www.cleaninginstitute.org. Retrieved 2023-01-29.
  11. ↑ "Stain Removal Techniques". HowStuffWorks. 2006-03-30. Retrieved 2023-01-29.
  12. ↑ Stefaniak, Aleksandr B. and Christopher J. Harvey. “Dissolution of Materials in Artificial Skin Surface Film Liquids.” Toxicology in Vitro. Vol. 20. Pgs 1265–1283. 2006.
  13. ↑ Lansdown, Alan B.G. “Hair Dyes and Hair Treatments.” http://www.chemistryexplained.com/Ge-Hy/Hair-Dyes-and-Hair-Treatments.html
  14. 1 2 Wolfram, L.J. and H.I. Maibach. “Percutaneous Penetration of Hair Dyes.” Dermatological Research. Vol. 277. pgs 235-241. 1985.
  15. ↑ Safety and Health Topics: Ammonia
  16. ↑ Raber, Linda. “Hair Coloring.” CENEAR. Vol. 78 Number 11. Pg. 52. March 13, 2000. http://pubs.acs.org/cen/whatstuff/stuff/7811scit4.html
  17. ↑ RTECS:BO0875000Effects of Chemical Substances | CDC/NIOSH
  18. ↑ Isopropyl Alcohol
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