Put your paint on ice

[Steven Sweeney]

Try a loose cover of Saran wrap before depositing in the freezer. This will stick to your palette and help protect the paint from the drying effects of frigid air.

I've watched others use a Tupperware container in similar fashion. They'd carefully pick up the unused paint from the palette, leaving behind any parts that had gotten mixed up with other pigments, transfer the paint to the rim of a small plate, put the plate in the container, snap on the lid and stick the whole thing in on top of the frozen meat loaf leftovers. Then you're free to finish cleaning up your palette for the next day's start.