I don't wash show quilts, but I do block them. That's critical to have them hang their best.
A good book to take a look at if you're intereested in showing quilts, both from the actual quilting side and from the showing side, is Karen McTavish's Quilting for Show: A Practical Guide to Successful Competition Quilting. It covers binding, sleeves, burying threads, blocking, trimming, what judges want, what their comments mean, many quilting tips, plus a lot more. It comes with a DVD as well.
Good luck on your entry, Stitch!