Buckeye lady -- yup, I've had that too, bunch of stuff went into the basement in this house when we moved in and didn't really discover how damp some parts were for about a year and a half
The good thing is, you really do not need very many canning lids anyhow

Pretty much just enough for the max # jars you might can in 1-2 consecutive days, in each size. (Unless you want some extras for gift-giving, or for if you store some canned goods where kids or very rambunctious pets might get to prying at 'em or bowling 'em around).
Really rusty ones being retired... you can wire them together to make a 'rack' for the bottom of a pot to use it as a canner or steamer, although I dunno *how* rusty I'd want rings going in my good cooking pots. I bet you could use them for a mobile/windchimes/garden-art, with or without a coat of paint, if you like doing that sort of thing.
framing fowl -- it's probably still worth taking the rings off (and washing both them and the parts of the jars they were covering, as some jars may have some icky stuff there by now), to prevent further icky stuff or rust. It's not like you *have* to do it but it makes the rings last a lot longer and it makes the threaded parts of the jars (some jars) a lot less gross when you eventually go to open them
Good luck, have fun,
Pat