How do i get that black scale off the bottom of my nu wave frying pan?

use a mixture of baking soda and water in a paste for the least abrasive cleaner

try laying a fabric softener sheet in the pan. Pour hot water over it and soak overnight.

If it's on the outside of the bottom I would carefully scrub it with cloth and a paste made out of baking soda.

Try sodium peroxide and Baking soda

I recommend sprinkling some baking soda on the stain and spraying some rubbing alcohol on the baking soda. Let it sit for 5 or 10 mins and then scrub with an old tooth brush. This is, of course, for stains on the outside of your frying pan.

I have the red copper pan with the ceramic finish. Did you season it before you used it? and do you use spray oil? do you cook on medium heat? those things I have found contribute to sticking. I brought this pan for 3 of my clients and sticking occurs when you didn't season it before using, cooking with spray oil and cooking at too high of a temperature.

PS I just soak mine in the sink with hot water and a bit of dish soap, leave for 10 mins. use a plastic spatula to scrap off the bits and a dish brush.