I don't wash my fabrics but I do dunk them into a pan of home-made starch and then put them thru my home-made wringer and hang them to dry, the press before I ever cut into the fabric. This most times helps the fraying to be minimal. Also by starching beforehand I find which of my fabrics might bleed too. If they do I can dunk them into vinegar. I've also started adding vinegar to my spray bottle of water I use to mist my fabrics when I press them as well as during my process of making the blocks.