Is Bar Keeper's friend safe to use on cookware?
Yes it is completely safe. It is even recommended by the manufacturer.


  •  To get rid of stuck-on food or discoloration, and stains from using too high of a heat, we recommend cleaning your All-Clad with a product called Bar Keeper's Friend. 


Bar Keeper's Friend even has a cookware specific cleanser, Bar Keeper's Friend Cookware. 



I'm not sure of the difference between this and their regular cleanser, since they aren't required to list ingredients, but it is marketed specifically for cookware, and priced equivalently.

Other manufacturers recommend this product as well, as noted on the BKF Recommendations page.

You should also check out this question on how to remove brown stains. The accepted answer there is BKF. If you have something particularly terrible that BKF can't handle, you can always use gun cleaner, though I daresay your wife will say no to this. :-)