Developing Old Film

Does anyone have any advice for the development of 15-year old TMax 400 and Ektapan 4x5 film?

The filmbase+fog is pretty hefty now--it obviously wasn't frozen. Scanning allows optimizing contrast, but regular analog printing is very challenging. I was wondering if there was an additive that can help reduce the age-based fog. Using XTol, the film speed still seems to be pretty good, but the snap is lacking when you look at the negatives.

Any suggestions besides the trash?

You can add benzotriazole to the developer, but it will lower the film speed, so it's only a good idea if you haven't shot it yet. I've never done it, so take it with a grain of salt. Hopefully, someone who has done it will chime in.

I'm hoping for some illuminating answers as I have a dozen or so rolls of Tmax 100 shot 20+ years ago I'd like to develop one of these days...