The kettle has only been in use about a month. The sides and bottom look so gross now I am replacing it. My stainless steel kettle never had this problem. I have never boiled this kettle dry, or even boiled it with less than the recommended amount of water. I am concerned there is something leaching out of the bottom into my water to cause this discoloration. I wiped the sides with vinegar and the paper towel came out black. But vinegar does nothing for the stain on the bottom.