Classification of Stains

How stains are grouped so the right removal method can be chosen

The system used in the Ohio series for classifying stains on washable fabrics is not the only one in print — other books suggest different methods that also work — but classification itself is indispensable: a stain's class decides its treatment. This sheet explains the grouping logic, which sorts stains by what they are made of — water-based, greasy, protein, dye, and combination stains among them — because each class answers to a different agent: water and detergent, solvent, enzyme or bleach chemistry. Identifying the class correctly is the step between guessing and treating.

Several fabric swatches each bearing a different kind of stain — grease, coffee, ink and grass — arranged in a labeled row, no people

Classification of Stains

Quick and Easy Stain Removal Clothing & fabrics  Fact Sheet Directory  Stain Removal  Care Labels  Fashion Education Directory  Apparel Research  Fashion Schools  Apparel

Classification of Stains

The system used here in classifying stains for removal from washable fabrics is not the only one that has been used. Other books or sources may suggest different methods that also may work. The purpose here is to describe at least one method that should give good results using readily available consumer products or supplies if used correctly.

This stain classification system starts with stains that require similar treatment and are easiest to remove if treated promptly and correctly. Stains that require two-step or special treatment are listed last.

Protein Stains

Soak in cold water. Launder.

Fresh protein stains can be removed by soaking and agitating in cold water before washing. These stains contain other ingredients besides protein, but it needs treatment first. If hot water is used first, it cooks the protein, causing coagulation between the fibers in the yarns of the fabric, making the stains more difficult to remove. If protein stains are dried or old, scrape or brush off crusted matter (if any), then soak in cold water using a detergent or an enzyme presoak product.

After treating the stain, launder in warm (not hot) water, rinse, and inspect. If stain remains, soak an additional half-hour, then rewash. Bleach may be necessary if the stain was colored, such as baby food beets, strawberry gelatin, or ice cream.

Tannin Stains

Do not use soap (bar, flake). Use detergents.

Fresh tannin stains are usually removed by detergent (not soap) washing in hot water (as safe for fabric) during laundering without any treatment. Use of soap (bar soap, soap flakes, or detergents containing natural soap) will make a tannin stain permanent or at least more difficult to remove. Be sure to check the ingredients list of your detergent for soap. More brands now include it for economic reasons. Old tannin stains may need bleaching for more complete removal.

Oil-based Stains

Use heavy-duty detergent with hot water.

Oil stains can be removed by pretreatment with a heavy-duty liquid detergent, an aerosol petroleum-based solvent pretreatment spray, or a pump-type detergent-based pretreatment spray. If these products are unavailable, you can use a powdered detergent that is mixed with water to make a runny paste and apply that to the stain.

The heavy-duty liquid detergents or aerosol sprays are more convenient and effective. Work the full-strength heavy-duty liquid detergent into the stain or spray with the pretreatment product, then wash the garment using hot water (if safe for fabric), the recommended amount of detergent for a regular laundry load, rinse, and inspect before drying. Repeat this treatment if removal is incomplete the first time.

Dye Stains

Need detergent wash and bleach as safe, for fabric.

Dye stains are very difficult to remove. First,pretreat the stain with a heavy-duty liquid detergent, then rinse thoroughly. Soak the stained garment in a dilute solution of all-fabric powdered bleach.

If the stain persists, and the garment is white or colorfast, soak in a dilute solution of liquid chlorine bleach and water. Bleaching damage to colored garments is irreversible. To decide if a fabric can be bleached safely, use the test described previously. If the stain is not removed in 15 minutes, it cannot be removed by bleaching and further bleaching will only weaken the fabric.

Caution: Since bleaches can alter the color of a fabric as well as the stain, bleach the whole garment and do not try to bleach just a spot.

Combination Stains

Two step treatment: (1) Remove oily/waxy portion, (2) Remove dye portion using bleach as safe for fabric.

Combination stains contain a variety of ingredients, but these stains usually have an oily/waxy component and a dye or pigment component. Use the procedures recommended for removing oil stains first.

Step 1 procedure depends on whether stain is in Group A or B as follows:

Group A. Spray or sponge with drycleaning solvent (perchloroethylene, trichloroethylene) then rub with heavy-duty liquid detergent before washing.

Group B. Rub heavy-duty liquid detergent into stain before washing.

After you've done the procedures above, do step 2-removing dye stains. Start with an all-fabric bleach because it is less damaging to colors and fabrics. Use liquid chlorine bleaches for tough dye stains, if fabrics are colorfast to bleach.

Special thanks to Iowa State University for allowing us to reproduce this information.

Reproduced with permission from the Cooperative Extension Service, Iowa State University, Ames, Iowa, 50011.

Prepared by: Janis Stone,
Textiles and Clothing Specialist,
Iowa State University

Treat the Class, Not the Spot

Two stains that look alike can need opposite handling: a greasy mark yields to solvent and is spread by water alone, while a sugary drink stain is water-soluble until heat caramelizes it into a dye-like stain. Classification replaces appearance with composition, and the sheet's classes map directly onto the series' procedures — once a stain is classed, its treatment page, its solvent and its cautions are all determined. Combination stains, such as coffee with cream, are treated in stages, one component at a time, in the order the classification prescribes.

When the Stain Is Unknown

Classification has an honest edge case — the stain nobody saw happen. The series handles it on its own sheet (What If You Don't Know the Stain?), with a cautious sequence that starts with the mildest treatments. The classification sheet's contribution is diagnostic: fabric, location, color, odor and surface feel are the clues that usually place an unknown mark in a probable class before treatment begins.

Common Questions

Why classify a stain before treating it?

Because treatment follows chemistry: greasy stains need solvent, protein stains need enzyme action without heat, dye stains may need bleach — the wrong class of treatment can set the stain.

Is this the only stain classification system?

No — the sheet says plainly that other books use different groupings that also work. What matters is using one consistent system that maps each class to a method.

How are combination stains handled?

In stages, one component at a time — for example the grease element and the dye element of a food stain are treated in the prescribed order rather than with a single product.

More to Explore

More from Apparel Search: Education  |  Fact Sheet Directory  |  Quick and Easy Stain Removal  |  Body Measurements  |  Clothes Guide  |  Fashion Terms
You are here: Apparel Search » Education » Ohio State Fact Sheets » Classification of Stains