I wash everything. I wash the dark colors after letting them sit in a vinegar soak for a while. As soon as I don't wash the darks, one will bleed. I wash all the other fabrics because I washed the darks and to get the chemicals out of them as well. To put body back into the fabric I press it using Mary Ellen's Best Press (a starch alternative). It smells so good! Everything goes to the laundry room for washing before it ever sees my sewing room. I do not, however, wash charm squares or jelly rolls, etc.