I just bought this jacket

http://www.bananarepublic.com/.....3qlv01.jpg

I bought it in a cobalt blue color. I wanted the green but my sister-in-law bought it before I did. I love the blue just as much though. Anyway, this is machine washable but I'm worried about the buttons. How could I wash this and protect them? They are just a little enamel disk glued into a metal button. I'm afraid they would get scratched up or fall out. Any suggestions? Thanks!