I mix peppermint oil, benzoin, camphor, wintergreen and inhale. Not only does it kill a headache, but it clears and focuses the mind and opens up the sinuses!
Use an old Vick’s inhaler nose thingie and add this mixture via hypodermic needle into the dried out batting in the inhaler, just enough to lightly wet it, but not enough to sniffle out any liquid. I use about 0.25 cc to saturate that batting, and be sure to spread it along the length of the batting and not just squirt it into one spot.