What to do with my gas tank?

The felt paper on my 65 Dart was too bad so tossed it. You can buy repros for $$$. I just use a few strips of closed cell foam w/ weatherstrip cement. I don't want anything holding water up there anyway. My brother rusted the top of his 73 Duster tank when he spilled water in the trunk and it sat on the depression there. That was in FL where stuff never dries.