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Pills are small balls of tangled fiber that form when loose fiber ends work out of the yarn, rub together and knot. You cannot stop every pill, but you can cut pilling a lot by choosing the right fibers and changing how you wash and wear knitwear.
Pilling is one of the most common fabric tests I have seen fail in my 14+ years in fabric development. Here is what causes it and what actually helps.
Why sweaters pill
- Short fibers: short fibers have fewer twists holding them in the yarn and slip out easily.
- Loose, soft yarns: low-twist, fluffy yarns feel lovely but release fibers faster.
- Friction: underarms, cuffs, bag straps and seatbelts rub the surface.
- Strong synthetic fibers in blends: polyester and nylon do not break, so the pills stay anchored instead of falling off.
- Rough washing: agitation and tumbling rub the fibers together.
Which fibers pill most
| Fiber | Pilling tendency | Why |
|---|---|---|
| Cashmere | Moderate to high | Very fine, soft fibers; short fibers pill quickly |
| Merino wool | Low to moderate | Longer fibers; superwash merino pills less |
| Cotton | Low to moderate | Pills mostly on fleece and brushed fabrics |
| Acrylic | High | Pills easily and the pills stay attached |
| Wool-polyester or cotton-polyester blends | High | Strong synthetic fibers anchor the pills |
| Linen, silk | Low | Long, smooth fibers |
How to stop pilling
- Wash less often. Air knitwear between wears.
- Turn sweaters inside out before washing.
- Use a gentle or wool cycle, or hand wash, and a mesh bag.
- Wash knitwear separately from jeans, towels and anything with zips or Velcro.
- Skip the dryer. Tumbling is a major cause of pilling.
- Reduce friction from cross-body bags and backpack straps on your best knitwear.
- Rotate sweaters so each one gets rest days.
- Choose better yarns: long-staple fibers, tighter knits and higher-twist yarns pill less.
How to remove pills safely
- Fabric shaver: fast and even on flat areas. Use light pressure and keep the fabric flat.
- Cashmere comb or sweater stone: gentler for fine knits; comb in one direction.
- Small scissors: for a few large pills.
- Avoid razors: they cut into the knit easily.
For washing guides, see how to wash a wool sweater and how to wash a cashmere sweater. To compare fibers, read merino wool vs cashmere.
Frequently asked questions
Not always. Some pilling in the first weeks is normal, especially on cashmere. Heavy, constant pilling usually means short fibers or a loose yarn. It can reduce friction slightly, but it coats wool and cashmere and is not recommended on them. Gentle washing works better. Polyester fibers are strong, so pills cannot break off and stay anchored to the surface. Occasional, gentle shaving is fine. Over-shaving thins the fabric, so only remove pills when needed.Does pilling mean a sweater is low quality?
Does fabric softener stop pilling?
Why do my polyester-blend sweaters pill so much?
Is it bad to shave a sweater?