We have 3 lots, all about 1/4 acre each. Our home is one the lot to
the north, the other 2 are to the south of us and are vacant. I mow
everything weekly, the lots are full of trees, shrubs, etc.

Some idiot seems to have dumped cooking oil on one of the sections (I
know who it is, but I can't speak spanish and they can't understand
english). What's the easiest way to fix this? The grass seems to have
died off. I am thinking of digging the affected area out, filling it
back, and replanting. Then maybe exterminating the person who did
this crap. :P