I know this is a pretty old thread...but I did it. I put my black signature Julianne in the washer.
The Julianne had belonged to my niece. I bought it off her pretty cheap - she just wanted rid of it because an a-hole ex-boyfriend had bought it for her. Anyway, she was pretty rough with it and the lining was dirty and there were some spots on the very bottom I couldn't get out. So I figured what the heck!
I put it inside a zippered pillow case - I thought that would protect the hardware and medallion the best. I have a front loading washer and I put it in with some sheets for cushion. Gentle cycle, lowest spin setting.
It came out perfect. I stuffed a clean white towel inside it and let it dry. Still have a small spot on the bottom, but other than that, it looks great!
I wouldn't make a habit of it, but I wouldn't be afraid to do it again.