Works wonders. Just a little spray on the most filthy glass - even creosote, leave for a minute or so, then wipe and you've got clear glass again. Do not get it on your skin (if you do wash immediately) - it burns. My advice is to wear cheap disposable rubber gloves, get an old pillow or cushion, take the door or doors off the burner if you can, lay on the pillow and then clean the glass whilst it's flat - then you don't get drips on your floor and get an even coating with less spray needed. Wipe after a minute or so with kitchen roll, then replace the door(s). Job done.