answer:I don’t know the answer but I like the question. As far as I know you can’t put much reverse current into a non-rechargeable cell of common type/chemistry without inviting a problem with leakage, fire, explosion. I will guess that a very slow and small charge in reverse, with a suitable survey of the state of the battery before and after might be able to get away with it. I.e. if you have some voltage and current capability at time A, send measurable but slight reverse current (too small to cause a fire or explosion), and re-assess the voltage and current capability, that could tell you a lot. If the output capabilities don’t change, then Don’t Charge, if they improve then for safety’s sake re-test a few times with slightly larger reverse currents. It’s not practical to do that manually on a regular basis, but an automated state-machine controller on a charger could do that evaluation for you.