I don't know about waxing, but my late ex-father-in-law was big on buying a case of name brand canned veggies and fruits when on sale. After he died I was helping clean out some of his stuff, and found many cans that were bulged and leaking nasty looking thick black goop. The cases were not dated, but none were over five years old. Admittedly, they had been stored in a non-climate controlled garage in central CA, so they got pretty warm in the summer and kindasorta cold in the winter...