If you choose to use an old keg to create a 'keggle' brewpot you might want to give your brew setup a little extra something by polishing your kegs. If you start with a pretty decent keg it will help. If they are beat to death like a couple I have, you first have to start with 220 (or courser), and then work your way up until you have a clean smooth surface to start polishing. Eastwood is a great place to start for polishing materials. On the keg below I used some discs from Lowes but I would recommend going to Eastwood since you will spend less and have a better result in the end. 
A few words of caution are in order however. If you use an abrasive disc for mild steel, don't polish you keg with it. Keep a set for stainless, aluminum, and mild steel, and don't mix. You will embed little rustable flakes into your keg if you do, and have a mess. Also while you can polish stainless and aluminum, you can't do this with chrome. Hit chrome with an abrasive and you will get nickel in a heartbeat when you burn through the chrome. Don't ask me how I know. According to George, if you want to clean up your chrome use soft scrub and 0000 stainless steel wool. Then wax it when you are done. If it looks like crap, do what I did and send it to George.
