Anything that has a tight lid is a good candidate for a small or regular cache. I have seen jars for peanut butter, garlic, Parmesan cheese (above), water bottles...and other canisters I simply can't identify. Usually they are camo-taped or painted, but not always, as you see above. Food jars can be tricky because it's nearly impossible to wash all the food smell out. I would be afraid animals would destroy it.
The smelliest cache I have ever found was made from an old garlic jar and filled with vampire paraphernalia. I wish I had taken a picture, it was too cute. There were no bugs around, that's for damn sure.