Oh, and I'll use the palette process above with oils and with enamels, too. The thinners just vary, that's all. With oils, I use mineral spirits, and with enamels, I've started using lacquer thinner. But the process is the same.
With those thinners, I do need a non-reactive palette, so that's why I have the ceramic palette. But if you use old CDs, you might be able to use one for a session, with a harsh thinner, before it attacks the palette, and then throw it out when you're finished.
I also know a painter who fashions a little cup out of kitchen foil, and uses that. He chucks it, when he's finished with the session.
Hope that helps!