Stains on wool: how to clean them without shrinking or pilling

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Why wool shrinks and pills

The wool fiber has a scaly structure on its surface (similar to fish scales viewed under a microscope). These scales are oriented from the root to the tip of the fiber and under normal conditions slide over each other without hooking. When wool is exposed to heat and movement simultaneously (such as in a washing machine at 40 °C with spinning), the scales open, hook together, and tangle forming an irreversible compact mass: that is pilling or felting.

Heat alone (without movement) also damages wool, but in a different way: it coagulates the proteins in the fiber making it rigid and fragile. Alkaline and enzymatic detergents also attack the keratin in wool because they contain proteases that degrade proteins, including those in the fiber.

The three rules for treating stains on wool

• Cold water always: never hot water, never warm water. Only cold water or, at most, room temperature (20-25 °C).
• No rubbing, only pressing: rubbing creates the movement that makes the scales hook. Only gentle pressure with a clean cloth.
• Neutral soap or specific for wool: nothing of enzymatic detergents, nothing of alkaline products. Only soap with pH 7 or wool detergent (Woolite, Perwoll Lana, lanolin soap).

Method for recent stains on wool

For stains from food, drink or any liquid on a wool garment:

1. Absorb the excess immediately with absorbent paper applying gentle pressure. Do not rub.
2. If the stain has a solid component (sauce, food), lift the solid with a plastic spatula without rubbing the wool.
3. Wet the area with cold water using a clean microfiber cloth. Press gently so the water dilutes the stain.
4. Apply a small amount of wool soap or neutral soap onto the damp cloth (never directly onto dry wool). Press gently over the stain.
5. Rinse with another clean damp cloth only with cold water, applying pressure.
6. Place the garment flat on a clean towel, give it the correct shape with your hands, and let it air dry away from heat.

Specific stains on wool

Red wine: Absorb immediately. Apply carbonated water (carbon dioxide helps push the pigment to the surface) pressing with a cloth. Then neutral soap with the pressure method. Do not apply salt on wet wool because it can damage the fibers.

Grease: Apply cornstarch or talcum powder dry on the stain, let it sit for 20 minutes, and remove by gently shaking. Then use the pressure method with neutral soap for the residue. Cornstarch does not damage wool.

Blood: Only cold water, never hot. Blood is protein and heat fixes it in wool just like in any fabric. Cold water with a cloth pressing, neutral soap, and more cold water to rinse.

Oxidation or deodorant: Stains can remain yellow-orange under the armpits due to a reaction between sweat, the aluminum in deodorant, and the fibers. Diluted citric acid (a teaspoon in 200 ml of cold water) applied with a cloth may help. Always test on a hidden area first.

When not to act at home and take to dry cleaners

There are situations where the risk of intervention at home outweighs the benefit: virgin high-quality wool garments, extra-fine merino wool, blends with cashmere, permanent ink stains, deeply embedded motor oil stains, or any stain that requires rubbing. In these cases, take the garment to a dry cleaner specializing in delicate clothing and always indicate the type of stain and how long it has been there.

• Do not use hot water: wool shrinks and the fabric hardens.
• Do not use enzymatic detergents: proteases degrade the keratin in wool.
• Never rub wet wool: it causes irreversible matting.
• Do not use a dryer: heat and movement together are the main cause of shrinking.
• Do not hang wet wool on a hanger: the weight of the water distorts the fabric. Always dry flat.
• Do not use bleach: it destroys the protein fiber.

• Stains on silk without damaging it
• Leather and suede: proper cleaning without damage
• Red wine on white clothes: do not set them with heat