I have recently come into possesion of a keg that i can finnaly convert into a brew kettle. (yes leagly dont start that disscussion) I can tell there was left a bit of beer in the bottom of the keg and lets say it "Born on date" was back in 03... being the brave man i am i plan to convert this bad boy into my brew kettle for AG. Question is what do i clean this thing out with? I assume there will be some nasty stuff in there so what can i clean it out with so as to kill the bad stuff?