I don't pre-wash anything ever. Glue basting can leave hard spots and funny looking spots though so I wouldn't use it for something I'm not going to wash. I would use spray baste. Make sure you get spray baste and use a light spray, not heavy. If you do decide to wash it at some point use a top loading machine and throw in some Shout color catchers. You'll usually find them on the top shelf somewhere in the laundry aisle.