It makes me wonder if we shouldn't be smelting a large cache of high-purity lead today and stashing it away deep underground, for the science experiments a few hundred years hence.
Considering the relentless increase of lead production in the past few hundred years [1], with every passing year, old lead is probably becoming more and more readily available, to the point that in another 100 years it might be cheaper to just scrape it off rusted car wheels/etc. than deliberately store it for such a long time. As long as we don't get too greedy with recycling.