I have 4 Folgers Plastic Coffee container caches,painted in the local cammo and sealed with indoor / outdoor clear spray. They've been out all summer and fall and they have held up well. The only one I had a problem with is the one a critter tasted. !!!! I am leaving them out this winter to see how they fare. One suggestion is to place them where they can stand upright, letting the cover do it's job.
Opalsns