I got very lucky this weekend and my brother in law came over with three kegs and said I could have them for free. I obviously took them thinking I could make an all grain system finally a little cheaper than I had thought. Question is I just had the welder plasma cut the tops and he said that they were aluminum. If these are aluminum I can still use them just not sure on what to clean them with because I heard that you can't use star San on an aluminum kettle.