"burnish it" or "burn that shit"?

My father apparently has a piece of rusted metal in his eye (?!). Since it's rusted, the metal piece can't just be pulled out. So my mother said they were going to "burnish it out." I thought she said that they were going to "burn that shit out." She laughed and laughed.

I suppose "burnishing" is a lot less traumatic than what I thought was going to happen!