One mistake I made with a cantenna was letting it sit on a concrete
floor. The bottom of the can rusted through from the outside. The
replacement can got a good coating of zinc chromate primer, followed
wirh red oxide, then acrylic enamel auto paint.

Jimmie

Mine was always inside and never rusted. I have seen them rust outside
though. I put mine in a tray, worrying about seepage getting on the carpet
but it would only pool up on the top.

Might be worthwhile to shoot the new can with BBQ paint.