Hi,
I have the same teapot, and have never used any abrasive scrubber on it. It did however have accumulated spots of grease that could not be removed with soap and a soft dish cloth. How I have been able to remove them, is boil a full kettle of water in the teapot. So it is nice and hot. Then get a soft dry cotton towel, and then gently rub and buff the grease spots off. No abrasive scrubbers. Just a hot teapot and a soft cloth. It will look like new!

I do not understand why i must pay all I want to know is how to clean the greae from the Alessi non electric teapot so far I have tried 10 different produsts nothing works. thanks