User blog comment:Neeeeeeenja7/Experience Farming? And 1 other question?/@comment-1761215-20100428025611

Pestilent defilers are a random drop. Any good corrosive/incendiary revolver/pistol/sniper (whatever you use) would work. Note that some of the enemies in knoxx are immune to a certain element ex: shocktroopers are immune to shock. A corrosive/incendiary bloodwing could help. I personally used a semi-auto sniper for knoxx as some enemies are fast.