I have several hundred pounds of wool that have felted. Look for men's long wool trench coats if you can. I got a man's 6x (yes 6) once for $2.50. Cut out the satin or silk liner. Save if you want. Great for crazy quilts. Cut or pull out any fused stabilizer. Wash in the hottest water possible. Dry in really hot too. NO fabric softener. Will just dull your rotary blades. Try to get 100% wool. Any other fibers and it may not felt...then, have fun.