When I complete a painting project, I usually have some paint left over in the paint can that I store for later use. After much time has passed (often year(s)) I need to do some touch-ups, and when I remove the lid from the paint can there is often a bunch of rust around the mouth of the paint can, and possibly also the lid. This rust inevitably flakes off and falls into the paint.
Is there a way to prevent this rust from forming in the paint can? If not, is there a way to remove rust flakes from paint?