I don't wash any of my fabrics but will starch them heavily, hang to dry and then press. If they're going to bleed, they'll bleed in my starch tub. When I press them, the heat should help to shrink them somewhat in my opinion. I mist them before I press. Have found out the hard way, do not bother trying to wash or starch the pre-cuts as they will distort terribly. I no longer will buy pre-cuts for that reason. Am trying to use up what pre-cuts I have in patterns asking for a cut just smaller than the pre-cut so I can cut the edge off.
Also no one but no one uses my rotary cutters. I have them marked for what they are used for.