[stoppingdown]

I've not used a flash for about ten years, some time before moving from Nikon to Sony. At the time it was (seldom) used for fill light in bird photography (with the Better Beamer). I still have a bunch of AA NiMH batteries that haven't been used since then.
Now I bought a small Meike Mk-320S for macro photography and AA batteries are useful again. I'm trying to guess whether it is safe to reuse the old ones, or whether there are risks of fires, chemical leaks etc...
Of course the problem is not to buy new NiMH batteries, they are cheap, but to avoid to dispose things that are a special waste.

---

Ah, I forgot another possible problem: the Mk-320S is able to recharge the batteries by connecting to a power source and of course I don't want to risk to damage it, even though it's cheap.