Menthol Shelf Life

[jiroband]

I have menthol crystals that about 4 years old. Do they "go bad" (lose their potency), or do they just evaporate away? In other words, do the menthol crystals that remain after 4 years still have the same strength they had originally when purchased?

 

[carebear]

good question. i'll ask my menthol friend.