Further to my previous comments: to summarise...

If there is visible grunge on the surface, it should be gently removed mechanically, perhaps with the addition of an appropriate gentle non-damaging cleaner - if it is responsible for the odour, that is the quickest method.

If the odour has permeated something, use something like Nilodor - a drop on a tissue, placed with the instrument in a sealed container, placed in a moderately warm (not cold) place (extremes may cause damage!) - note that each 10 deg C rise in temperature doubles the speed of chemical reactions.

I forgot to mention that you can also get 'sneaker sniffers' - inserts of activated charcoal - that will absorb odours - this may be an easy way if you can't get Nilodor - place in the sealed container with the instrument. This may also help larger instruments, such as guitars in their cases.