How to Make Felt From Sweaters
- 1). Put the sweater in a washing machine and fill it with hot water. Balance the load with a light-colored towel so that the washing machine doesn't shut off when it spins. Add a gentle detergent to the washer if your sweater is dirty. Run the washer on its most vigorous and longest setting. When subjected to heat and movement, the wool fibers tighten up and shrink.
- 2). Complete the felting process by placing the wet sweater pieces in a warm to hot dryer. If the sweater is not as dense as you would like it once it's dry, wash and dry it again.
- 3). Cut the sweater apart with a pair of scissors. When cutting, stay as close to the existing seams as you can. When you cut the sweater, the edges should not fray. If they do, stop cutting and wash and dry the pieces again.
Source...