I found out the hard way that a wet acrylic palette lasts a few days, max. After that it starts to smell a little earthy. I forgot about mine when I went on holidays the other week and when I got back, well, let's just say I'd started my own science experiment. A whole ecology was evolving in that container. But otherwise, it's brilliant and I love that it reduces paint wastage and keeps the paint at a consistency I like even better than what comes directly out of the tube.