Regulatory and Environmental Consulting
SOME STAINS CAN’T BE FROZEN AWAY
by Nathan Schiff, Ph.D.
Associate Editor - Institutional, FABRI CARE
As Monica and her mother have shown, freezing a blue dress only preserves the stain, but doesn’t remove it. The first rule in removing a stain is to treat the spot promptly. If stains are allowed to "set", they become more difficult and in many cases impossible to remove. The different type of stains are derived from either food, biological fluids or medicinal and cosmetic preparations. The standard procedure is to first sponge the affected area with cool water then blot up as much of the stain as is possible. Treat the affected area with a stain remover or pretreatment chemical for 15 to 30 minutes, followed by normal laundering using a bleach-containing detergent. Colored fabrics require a color safe bleach such as peroxide, whereas hypochlorites work best on whites capable of tolerating chlorine bleach.
The pretreatment chemical is usually a concentrated blend of detergents and solvents, such as Shout, Spray ‘n Wash or Clorox Stain Out, or a paste made by mixing powder laundry detergent and water. Spot removers are designed to solubilize and loosen most fresh stains, enabling them to be easily removed in the normal laundry washing cycle. Below are some example of difficult to remove stains from each of the different categories.
Aged food stains respond best to enzyme pretreatment, such as Ultra Biz. Enzymes are chemicals which are produced by all living organisms. They speed up the break down of food residues (as they would during digestion), into simpler compounds, and are very specific towards the stain which they act upon. Proteases for example, are a group of enzymes, specific for breaking down protein such as egg stains, whereas lipases act on oils and greases derived from food stains. For oil and grease stains of non food origin, such as baby oil, hair oil or greasy ointments, pretreatment with a degreasing stain remover gives best results.
Tannin stains are made by coffee, tea, soft drinks or wine and their pretreatment requires a special precaution. Use of soap or detergents containing natural soap will cause the tannin stain to set and make them much more difficult to remove.
For blood stains which have "set", apply hydrogen peroxide (3%); obtainable from most drug stores. Add a drop of household ammonia to the stain, on top of the peroxide and leave it on for a few minutes. The ammonia restores faded fabric colors. Repeat the process until the blood stain fades, then launder the garment in the normal manner.
When fresh, urine stains are acidic and can easily be bleached out with a solution of sodium percarbonate and water or a paste of granular laundry detergent, containing an oxygen bleach and water. As the stain ages, it turns alkaline and needs to first be treated with a solution containing equal parts of vinegar and warm water, followed by a hydrogen peroxide bleach.
For best results, first prewash the fabric in cool water in order to remove as much of the stain as possible. Apply an enzyme-containing stain remover for 15 to 30 minutes, then launder the garment in a color safe, bleach-containing laundry detergent.
Iron tonic stains need to be treated in the same manner as rust stains. Pretreat the stained area with a solution of 1 tablespoon of oxalic acid; available from most drug stores, to 1 cup of warm water. Mix the solution in a plastic or glass container. Following pretreatment, rinse the garment thoroughly with cool water, then launder. If the stain is not fully removed repeat the process. Do not machine dry as the heat from the dryer could set the stain.
When fresh, these stains can be removed by laundering the garment in a bleach free laundry detergent. Detergents which contain chlorine or oxygen bleach can set the stain and make it more difficult to remove. If the stain still persists, apply a solution consisting of 1 tablespoon sodium thiosulfate (obtainable from photographic supply stores which sell film developing chemicals), in 1 cup of warm water. Rinse well and launder the garment in the normal manner.
Remember, whatever method or chemical you use, always test the pretreatment chemical in an inconspicuous part of the garment, to be sure it will not adversely affect the garment.
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