There is H2SO4 in 30% concentration, yes, you should not drink it, but in school we did chemical classes with higher concentration when I was 12 year old. Also it can be easily neutralized using chemicals available in every kitchen.
Led is indeed poisonous, but if you cast bullets, you know it will not kill you on touch.
In the military we would take batteries apart and exchange led plates for old plates an daily bases.
