I mixed some "stuff" and left a bolt inside a bottle about 3 months ago, solution is full of rust now and I wonder if it's safe to use.

Now you have a transdermal Iron supplement. Its probably a bonus. It will go through the skin, too much iron can give you diarrhea and headaches or worse on the high end. Bet, you use a marble next time?

Marbles are more expensive.

At least the last time I looked....

Thanks for reply. I didn't have marble on hand, but this time I pulled bolt out right after I done mixing it. After new bottle is gone I'd like to use old one up, just worry about the rust in it.

Hell just use it but be cautious.

I clean rust off of stuff all day with denatured alcohol (no gloves), surely if it posed any risked I would have had some issues, as well as many more in mechanical trades.

Cool, thanks for your help, man.