Yes, this is an issue for me . . . and it has been for quite some time. I really prefer using a high gloss polyurethane out of the can, rather than spray on, for many good reasons.
Yet, after use, even though I try my best to clean the rim and the lid, if the can sets on the shelf for awhile I often notice a "skim" or "skin" on the top when I reopen to use, indicating I am not getting a good seal.
Any suggestions on getting a good tight seal?