I was pretty excited when I realized you can buy fairly pure, concentrated sulfuric acid in the cleaning isle at Walmart. Nothing cleans dirty glassware quite like it! Accidentally got a stopper stuck in a flask? No problem, add some H2SO4 and just pour the stopper out a few days later.

Restricting what people can buy because they might hurt themselves with it doesn’t work (because everything can be misused) and only creates problems because sometimes restricted things turn out to be really important.