Saving a Red Top

[Cardboardcat15]

I have an old Optima Red Top that I used in my car for almost 2 years sitting here. It's been in a closet, unused for probably a year. It's been through 2 6+ hours of forgotten headlights, and numerous other things. My question is:

Is there be a way to possibly save this battery? I want to use it for a small project soon, or just keep it for backup. The battery sits at around 11.9 all the time. I've charged it a few times, but only to have it fall down to 12.0 flat-ish 8 hours after charging. Also, the battery heats up when it's charging after a while.

Is this thing save-able? Or is it trash?

[Lbox88]

charge it, then discharge it several times? worth a try I guess, better than just trashing it and getting another batt without trying to save it.

[n8ball2013]

connect a known good battery to it to charge it back up. So you'll be charging both batteries at the same time.