I've seen advertised charges that will recharge ordinary non-rechargeable
batteries. Are these any good ?

I used to make chargers that recharged ordinary batteries when I was
a kid, they wern't all that successful as I remember, but the technique is
called "dirty DC".

Googling that term seems to be useless, as an AC/DC tribute band
uses the same name!

If you are interested, Googling
"dirty DC" "zinc carbon"
will give you the right info.