I have 4 of these Rust-Oleum Restore Semi-Transparent One Coat cans still with the clips on them that I received from Rust-Oleum last summer. They are stored in our garage year-round. I noticed a couple of days ago that the lids were starting to open up, and a couple of the cans had their bottoms bulging. All the lids are a plastic material. Any clue what's going on? Should I toss them?