Remove soot from ceramic (plate or pure)

I have a ceramic Pure in the gas grill ... when the fat burned in the grill for a short time unobserved, the white pure was completely black. Despite scrubbing in hot water with Spüli nada ... :-(

I then used the (careful, unintentional advertising) White Stone - or maybe the Obenlandreiniger (both absolutely environmentally friendly), with which I normally make my stainless steel sink sparkling (looks like polished) ... and lo and behold, the ceramic Pure is clean again!

Ergo - absolutely eco-friendly and yet great!