It's easy, I don't join swaps that require prewashing. There are swaps out there that stipulate NOT to prewash.

I do them by hand in the sink they are scraps, meaning not yardage, anything from a 1/2 yard and smaller. Once rinsed I hang them on the clothesline and press while damp.

Thanks for all the responses. I think I may have a pair of pinking shears somewhere! I know I had them back in home ec in HS many moons ago :lol: I like the idea of hand washing also. I have a lot of 1/4 yd cuts and they were a knotted mess when I took them out of the washer! I love hearing how other quilters do things