Clean oven glass / firing glass with cleaning pad
In order to clean the glass of the furnace or chimney of soot, I recommend cleaning pads (actually for cleaning pots and pans), one is e.g. Abrazo. I have already tried the tips with ash and black tea. This worked reasonably, but is not comparable to the result of these pillows. It also gets rid of stubborn soot and does not rub the glass with it any more or less than e.g. with the ashes.
The glass looks like new after cleaning.