Chef'sChoice 692 International Keep Hot Thermal Electric Kettle, 1.5-Liter, Red

I will be sending this Chef's Choice pot back, which is a shame because the water does stay hot for about 4 hours. However, when I make a cup of instant coffee with this water, I notice weird floating looks like grey slimy stuff on top of my coffee. When I looked inside the pot there is a collection of grey stuff on the bottom of the pot. I took a brush and cleaned the pot & sure enough this grey stuff is coming from whatever material this pot is made of.

Exactly as described