As for acetone, you do know it is present naturally in small amounts in fruits and so on, right? But when one buys it in industrial grade (or general unguaranteed hardware store acetone), it could very well have some heavy metal or other contaminants (maybe in some cases not, or maybe too little to have any negative health repercussion, but there is the possibility, which some people dont want to risk)
I usually get USP grade acetone, which is basically what one could call food-grade. Its significantly more expensive than normal acetone but I feel its worth it because often enough depending on what process im doing, acetone is the last product to 'touch' my final product, so considering I am putting it inside of my body, I rather make sure that any small amounts of impurities present will be benign