After 1 month of burning my new Fireview I inspected the catalyst. It was very easy to get at. Just lift up the top, remove 2 bolts, and lift out. There was no sign of any blockage, just a little loose white fly ash that I vacuumed out. The glass still stays spotless. I only cleaned the glass a couple times because of a couple smudges and a little fly ash stuck to it. Very impressed with this stove. Easy to operate, little maintenance, and more heat with less wood.