Try licking a MyClone. They have a special coating in their paint that is designed to make them taste bitter to infants in order to elicit them to spit out small parts (and also to discourage them from swallowing said parts). You may not taste anything as infants have a different palate from adults. I still remember baby food being the bomb when I ate it as a baby, but when my wisdom teeth came out, I ate baby food again because I was in too much pain to eat solids - and EEWWW... yuck!

Anyway, the word mint can be used as an adjective to describe something being in unused or appearing to be newly made and never used. In the field of collecting, it originated from stamp-collecting to describe a collectible that is in its original and unused condition. (Reference)
Collins Cobuild Advanced Learner's English Dictionary states; "...something that is in mint condition...is in perfect condition."

The smell (and possibly) taste that you can detect on new action figures is actually the paint. Mmm... paint fumes high fresh...