A couple of friends that moved out of town recently left us a nice, heavy grill pan of unknown origin (we live in a student apartment building, so people who are moving out often leave stuff they don't want in the hall so others will take them). I was quite curious, so I looked at the bottom of the pan and googled the name... and ta-daa, there it was. Cast alluminum, just like this one, only (a lot) more battered. Now the big question: how do I clean this? From what I understood from the description it has some kind of non-stick coating (some kind of seasoning...?). Am I supposed to treat it like cast iron?