Clearly I'm not trying to say you shouldn't worry about the warnings of cleaners. Especially when one says mild vs. serious. You should use whatever works for you. 

Sorry no pics gang but the Makers Mark definitely made it better. I think I will need to do it a couple of times to get it nice. But you have to make sure and use good gloves. I had a hole in one of the gloves and there was a fairly painful burn on my skin there.

Just ordered 12oz can powder of Barkeeper's Friends.  For $7.79 and free mailing.  My RT 590 needs a little external cleanup. Not worried about the inside (discoloration is no problem), I just keep it clean with occ. scrub down with old rags and soapy water.  See no sense in restoration to new on inside. Powder is said not to be abrasive but will go with the grain anyhow. Thanks for the head's up.   

 What I do with my Memphis (all stainless steel) is to spray the areas such as the top, hopper lid etc, the ones that always get slightly dirty, with a light misting of full strength Simple Green. Then wipe using one

piece of a paper towel. That keeps it amazingly clean. Good enough to last until it's time to perform my yearly clean up where everything, inside + out gets cleaned. To make this work I had to start with a clean

pit and Simple Green it after every use. I found if I didn't do it this way the build up became amazingly hard to remove.