If I, for example, use an Impish Mint on a Ferrothorn, will the mint go away like a Rare Candy or Potion does? Or would I be able to use the same mint again again on another Pokemon?
The Nature Mints may only be used once each.
Source: Experience You can also make an educated guess. Why would you be able to get multiple if one could be used over and over?
Hope I helped!