The lead danger is real, but it has been exaggerated. Range officers at shooting ranges, and some competitive shooters do show dangerously increased lead levels in their blood, but unless you spend all day every day at a bench grinder cleaning up old valves, you're not likely to show any ill effects. The guys who spent every day radius-grinding asbestos brake shoes back in the 1950's thought they were safe, too, as I recall.
I cast thousands of lead-alloy bullets every year, but I use a "Darth Vader" looking respirator and do as much of the wheel weight smelting and alloying as possible outside with a Coleman gas-burning stove. The indoor bullet casting gets done with an exhaust fan operating, and I'm wearing the respirator. Just use a few common-sense precautions like at least a dust mask, and wash any exposed skin after you'e finished cleaning the valves. No problem.
Jerry
