If you use the fine pine shavings for chicks, they'll eat them. I use bigger shavings. It's really cute when a chick picks up a large shaving and goes running around with it. It looks like its carrying a flag while all the other chicks chase it around trying to see what it has.
I haven't had that problem with any of my buttons. I keep mine on pine shavings that get changed regularly.
Soaking is the only way I know of to get those things off.