Normally your catalytic combustor requires little or no maintenance. Because it generates such high temperatures it is basically self-cleaning.
After the first burning the combustor should have a light gray powdery appearance. Should the combustor’s cells become masked with fly-ash, use a paintbrush or soft-bristled brush and dust the combustor gently.
Never use anything abrasive to clean the combustor. A vacuum cleaner may be used, but never use high pressured air to blow the cells free of any build-up.
Any cell blockage can be removed with the use of a pipe cleaner or a cotton swab. Should the combustor become masked with soot or creosote it is possible to burn the accumulation off by opening the bypass and building a hot fire. Once the hot fire is created, close the bypass halfway and burn for 30 to 60 minutes with the bypass in this position.
However, it might be wise to check and clean the combustor, if necessary, before each burning season and inspect all flues for creosote build up. Cleaning the flue when necessary helps prevent chimney flue fires.