The canned tomatoes that were all done at the same time, but my daughter has stored hers in a warmer environment than I have. When she opened a jar tonight the canning lid was all black. The tomatoes taste OK, but I'm afraid that there could be a problem with them. She says she can see other lids (through the jar) that also have black on the inside lid.
I remember an old saying; When in doubt. Throw it out!
I don't know if they would be any good or not. Did you can them together or did she do hers at her home? I do know that I was brought up that home canned goods should be stored in a cool place like an unfinished basement, you don't want it to be cold enough that the stuff will freeze, but cool.
Throw away like Keeper said when in doubt. There could be so many reasons why this happened that I wouldn't take the chance of someone becoming ill because of using.
I use to do a lot of canning. Sometime I would get some jars with black on the lids. If I remember right it was mostly tomatoes or peppers. Things with high acid. Can not remember if they had been canned for a while or not, but I always toss them out. You can not tell if they will make you sick or even kill you by tasting. As Keeper said When in doubt. Throw it out.