Please prewash. Recently I was working on a shower gift for a niece (placemats, napkins, tablecloth etc) her colours were black and a deep red. I thought I was safe to wash these colours together without thinking about the fact that two of the fabrics had white polka dots. I ended up with blacks and reds with pink polka dots. Needless to say I headed back to the fabric store to correct the situation. Lesson learned