Prewash any fabrics that you think might run. Throw a " color catcher" in the wash and it will pick up any loose dye. Most times I will run a second rinse and add a half color catcher sheet. If that half sheet is still white then I know the color will not run anymore.
Color catchers are found in the laundry section of your supermarket. It is a "Shout" project. ( I don't think it is sold in Canada.)