You spray the glass and it starts to dissolve the smoke on its own, then you wipe it with kitchen paper. It takes 2-3 passes, especially if there are stubborn smoke stains, but it makes the glass look brand new.

Good but it needs more quantity than the expensive ones! It leaves a blurry residue on the glass if you don't do it like 3 or 4 times.

Very good product. You spray it and without waiting it dissolves the smoke and dirt from the fireplace door glass. You clean it with kitchen paper just as easily as windows!