Pestilence - Mint
I think it is caterpillars. I didn't see the caterpillar when I took the picture of the black specks on my mint plant, but I noticed it when editing the pictures. There are big holes in many of the mint leaves, and nasty looking black spots on the leaves and stems. Caterpillar poo, maybe?
I'm pretty sure that's a caterpillar in the third picture. Can anyone confirm my conjecture and tell me how to deal with this pest?