Wool Sweater Wash

Steps

1. Fill a clean basin or sink with cool water (no warmer than room temperature). Add 1 teaspoon of baby shampoo and swirl gently to dissolve.
2. Turn the sweater inside out and submerge it in the soapy water. Press it down gently to saturate all the fibers.
3. Let the sweater soak for 15-20 minutes. Do not agitate, scrub, or swish. The soap will do the work of loosening dirt and oils.
4. Drain the soapy water without wringing the sweater. Press the sweater gently against the bottom of the basin to push out excess water.
5. Refill the basin with fresh cool water and add 1 tablespoon of white vinegar. Submerge the sweater and press gently a few times to rinse.
6. Drain and press out excess water one more time.
7. Lay the sweater flat on a clean, dry towel. Roll the towel and sweater together into a log shape and press firmly to absorb water. Unroll and repeat with a second dry towel if needed.
8. Lay the sweater flat on a drying rack or clean dry towel. Reshape it to its original dimensions (blocking) and let it air dry completely, flipping once halfway through. This may take 12-24 hours.

Why It Works

Wool fibers are covered in microscopic scales (similar to roof shingles) that open when exposed to heat, moisture, and agitation. When open scales interlock with adjacent fibers, they lock together permanently — this is felting, and it causes irreversible shrinkage. Cool water keeps the scales mostly closed. Baby shampoo is ideal because it is pH-neutral (around 5.5-7), which matches wool’s natural slightly acidic pH. Harsh detergents are alkaline, which swells wool fibers and opens the scales aggressively. The vinegar rinse restores the acidic pH after washing, tightening the fiber scales back down and giving the wool a softer hand feel. The no-agitation soaking approach relies on the surfactants in the shampoo to lift dirt without mechanical action, eliminating the friction that causes scale interlocking.

Tips

• Baby shampoo works because it is formulated to be gentle on protein (hair is keratin, just like wool). This is the cheapest effective wool wash available.
• Never hang a wet wool sweater on a hanger. The weight of the water stretches the shoulders and body permanently.
• The towel-rolling step removes about 80% of the water and dramatically shortens drying time.
• Position a fan near the drying sweater to improve air circulation and prevent mildew on thick knits.
• Most wool sweaters only need washing every 5-8 wears. Wool naturally resists odor and bacteria. Between washes, air them out overnight.