Having lived in a house without Air my whole life never seen this happen. Ye it does get north of 90 degrees here, and our barn and garage do not have Air, no cans did it that sat in them. Not a paint can all the way to Raid and brake cleaner nothing has ever done this. Dads old metal barn is as bad as a car in the sun. If it was heat they would have been popping off every time it hit 100 outside.