This question made me wonder whether this works.
A flask of acid can be used as a power component to add 1 point/ of acid damage per round to the effect of grease.
Grease (M): The grease is acidic and deals 1 point of acid damage per round to any creature in the area or holding the greased object.
Could I cast a burning grease with a flask of acid as a power component on an opponent's armor so that s/he is dealt 1 point of acid damage on round 1, 3 points of acid damage for the rest of the duration and 2 points on the round after the spell ends to the opponent?
When cast on CL 5 (when you get level 3 slots) that would be 5 minutes duration, which is 50 rounds.
Most armors should survive that because of hardness but unless it is removed that would mean 150 points of damage.
Edit: I missed that the feat mentions needing the acid or fire descriptor when I checked it. Sorry That should not have happened.