After buying a pawnshop horror guitar which smelled so bad of nicotine and stale booze that it couldn't be kept in the house, I suspended it over the bathtub filled with very hot water and alot of bleech in order to fume the stench away. It worked, but then the bleech left a faint scent which I simple aired away, followed by the baking soda treatment with the guitar in a case.

Smell be gone.

Peace, Mooh.