I've made quilt sized ones and I've always washed them and had no problem but I live in the city so it may be a difference in the piping system. I think the washed ones looks do much nicer plus if any threads break or seams you'll know in advance. You could wash it in a bucket/pan of water or take it to the laundry mat. They can also be made with fleece which will curl but not fray, it looks super cute. Denim jean fabric also works well but may have the same problems with the fraying. this time of the year fleece is on sale really cheap. I keep a lot of quilt blocks made for a last minute gift. I use my Accu cut machine. If you cut the fringe before sewing them together, which is what I did since I did it on my cutter you could wash the squares in a mesh bag and it might be easier.