Clean the glass a few minutes after loading fresh coal. Only open the load door a crack so draft can keep things going the right way and it will cool. This is how I cool mine for cleanings. Works great..
Anytime my stoves (wood in the shop; coal in the house) are set for anything but a long burn, I set my iPhone timer to 10 minutes. I can move on to something else and be reminded after 10 minutes that I need to circle back to the stove.