Sorry for not responding earlier
Fallout should expire on itself after a few turns. I don't think there is any way to speed this up.
I think of adding in 0.30 worker order to clear heaunted lands (at Knowledge of the ether perhaps?), and maybe one for fallout, too. But not sure yet.
Regarding exploits, I am trying to hunt them down.
This particular one will be gone in 0.30. Both mercenary spells are gone already, I am writing a new one, simillar to magnadine unique spell.