I recently purchased a stainless steel teapot and thought I'd give it a wash before use, but. as you can see from the design the inside bottom of the teapot has a very slight gap round the rim about a millimetre or two. I happened to run my nail around in-between the gap and discovered that it has a dirty black residue inside the the gap , like polish or grease. I tried to clean it up as best I can but I shall get one of those small bottle brushes to clean it better. Is this normal residue? I think its a bad design to have that inside the teapot albeit down in the rim.