I, too, usually wash my fabric, but I recently purchased Lisa Lam's (U-handbag) "The Bag Making Bible." She says she never washes fabric. Instead, she suggests that bags should be spot cleaned, not washed. I've got to say that I so seldom wash my own bags that I'm about to adopt Lisa's recommendations!
Thanks so much! That is great advice. I could probably send a little "Care Card" with my bags to tell the buyer to Spot Clean only.