Have 2 big stock pots that came from my Dad's house. One is 10 qt, the other 16 qt and marked Toroware by Leyse. They didn't get used on a regular basis.... generally for big pot of veggie soup. They're both great pots but badly stained inside.

I use them for stock or even hot water bath canning... before I found a whole canning set up at a yard sale. I'm thinking the staining came from tomatoes in soup?? Dark stains are pretty must just cosmetic, but wondering if there's a way to get rid of them? Seem to remember my Grandmother voiling water and adding... cream of tartar?? Maybe in combination with something else?

ANy ideas?