If the comb is plastic simply take the harp apart and soak the comb in warm soapy water. Then dry the comb and the smell will be gone. If the comb is wood.....take the harp apart take some grain alcohol(like white liquor sold in the liquor store) and clean the comb with a cotton swab soaked in the grain alcohol and blow dry quickly. Clean the covers with hot soapy water and the reed plates can also be cleaned the same way and you should also blow the reed plates dry with a warm hair dryer set to low air flow... These procedures should remove any smell. If this fails drink the rest of the grain alcohol and you won't care if there is a smell. Oh, I forgot... You have to reassemble the harmonica after the cleaning.. or it simply won't play well, at all.

Rayzor