I hate it when I go looking for a can of paint in my basement to do some touch up and find that I have to toss the whole can because of the rust around the top. There is no way I can stir it use the paint without rust dropping in the can to contaminate the paint. I happened to have picked up a Super Lid just out of curiosity and realized that the lid actually encompasses the inside and the outside of the metal lip around the top of the can. Vacuuming out any loose rust and wiping down the outside of the can, I slipped the super Lid in place, and was able to stir and then pour the paint into a replacement container, saving 2/3rds of a gallon. Excellent!