I borrowed the idea of a 'holding' palette for unused paint at the end of a painting session. I started by putting my glass palette in a box, then a plastic bag stored in the freezer. Worked okay, but I found I really enjoyed starting with a clean palette. So I started storing leftover paint on a white salad size plate, put it in a sealed plastic plate holder in the freezer. But the plate is hard to clean, so I went the ultra easy/lazy route, and save any usable paints on a piece of disposable palette paper, plop that into the bottom of a standard Ziploc sandwich container, pop the lid on, and throw it in the freezer. No clean up when the paint is used up, colors not being used can go right back into the freezer so the faster drying organics don't dry out, and it doesn't take up as much room in the freezer.
Postscript 4/3/14: Nothing stays the same here, so I ended up using a rectangular plain white tile (3x6") to store leftover paint. I made a little box with a fold over lid out of plain old cardboard, put that in a ziploc bag and it holds well for up to a couple of weeks. The organics will dry out no matter what, so I only save the mixes I might need again and the colors I know won't dry out.
Postscript 4/3/14: Nothing stays the same here, so I ended up using a rectangular plain white tile (3x6") to store leftover paint. I made a little box with a fold over lid out of plain old cardboard, put that in a ziploc bag and it holds well for up to a couple of weeks. The organics will dry out no matter what, so I only save the mixes I might need again and the colors I know won't dry out.
