We use unscented everything because DH is sensitive to smells. So I just wash the fabric same way I would wash the finished quilt. I use warm water & my regular detergent, with color catchers. If anything seems like it's a bleeder I'll re-wash with color catchers again and see how it looks.
I wash my quilts when I'm finished too - I usually use Elmer's to glue-baste so it's not an option to leave it unwashed! But even if I didn't use glue I wash the finished quilt at least once, sometimes twice if a cat gets on it before I can give it away - that way I can tell the recipient that it's tested in the washing machine and 100% safe to just toss into the machine at home.