They advise that aluminum brew kettles shouldn't be scrubbed, but in this case I would. The proper way to season one is to boil water in them and just wipe them out with a soft rag but leave the dull finish behind. To get the BLACK off I would use hot water and a green scrub pad "NO SOAP" of any kind and a lot of elbow grease. Then fill it with water bring it to a rolling boil for about 25 - 30 min and after it cools just dump the water and let it air dry.
