I would advise a little care/investigation here.
Quite a few years ago in our town there was a family in one of the low income areas tragically killed by fumes. It seems the father was supplementing his income with various sorts of scrap metal. One of these was batteries which he took apart himself and sold the lead to the salvage yard.
The separator plates these batteries was made of wood for the most part, although some may have been other material. They did burn these in the wood stove for fuel, due to a financial problem and the cold weather.
They all died, man, wife, and children. Seems the separator plates had absorbed material that produced toxic fumes. ( I don't know if it was lead or sulfuric acid that caused the problem)
So my question is does the lead used in batteries undergo any change and is there some sort of special handling needed compared to raw or plumbers lead, or wheel weight lead?
It's quite possible there is no cause for concern, and if so I admit my ignorance. If it was me I would do some serious research before using battery lead.