Why do you need to get rid of the leather? Get some that is thinner or tougher if you need it but from what I have read changing to lead causes other problems. Plus it is a pain to set up if you need to switch a flint in a pinch.

As far as your question goes I would not worry about lead poisoning if you just wash your hands and don't eat the stuff. Oh, yea don't breath the fumes either.