Lori, yes, the snails go after my mint as well! Who would guess the little guys would be so aggressive?
If your mint is in the ground, I would recommend transplanting it into a pot with a saucer to catch the water drainage. Then set the pot with its saucer into a saucer with a larger diameter -- about an inch between its edge and the edge of your water saucer.
Then fill the outer saucer with rock salt (the kind you get in boxes at the grocery store to make ice cream with). The snails will not cross the salt barrier because salt is lethal to them. Meanwhile the salt will not leach into the water or soil of your mint, nor will it be dissolved when you water your mint because you have the dual saucer arrangement. Hope this helps!