So I was at the pharmacy the other day, and noticed they had mineral oil and needing some to store sodium, I looked at the purity and saw that it was 99.9% pure. However, I had also found some from a chemical supplier, and I wasn't sure if theirs would be better - so I figured I would poll the audience- does everyone think / know if the mineral oil from the pharmacy would be pure enough to store my sodium, or should I get it from a chemical supplier? I try and stay away from buying things OTC (like H2SO4 drain opener, due to heavy impurities) but this is from a pharmacy, and is 99.9% so it seems like it would be pure enough...

Heavy mineral oil, intended for laxative use is quite pure, but needs to be deoxygenated and dried completely. Adding a piece of sodium (or better, potassium) and letting it sit for a week or two will accomplish this. Of course, you could just deal with a tiny bit more tarnish on all the sodium and throw it all in.