You should brush or vacuum ash off of the face of the catalytic every month during the heating season or anytime that the draft slows on your stove.
Cleaning the catalytic in the Kuma LE series is easy and only takes a few minutes. You do not need to remove the catalytic but you will remove a metal flame guard. You will need a 2" paintbrush and a can of keyboard dusting air.
Watch this video for instructions: