Home owners call in with questions regarding gas logs all the time, one of the most recent of which is why their gas log set is collecting soot. Most people know that gas logs are supposed to burn clean. The chimney flues through which the products of combustion from gas logs vent need not be cleaned so long as the logs are functioning properly, but the flue still needs to be inspected yearly.
Why then, does soot sometimes accumulate on gas logs? When gas logs are not functioning properly, soot can form. When gas is burned, the products are supposed to be carbon dioxide and water vapor, but hen the natural gas is not completely combusting, other byproducts, like soot, is formed and can accumulate in the flue system as well as on the logs themselves. Often times this occurs due to improperly placed logs, so that the flame is actually touching the log, cooling the flame, and preventing complete combustion.
What do you do when soot has accumulated on gas logs? First, you should have a professional come out to inspect and service the logs. The logs should be looked at and the chimney flue inspected as well. The professional will clean the gas logs and ensure that they are working properly. An improperly working gas log set which is not completely combusting gas has the potential to produce carbon monoxide as opposed to carbon dioxide, which is dangerous and potentially fatal.
You should never wash your gas logs. If you want to clean them on your own should take them out of the fireplace one by one, very carefully as to not damage them, and take them outside. I recommend cleaning them using a vacuum to clean them, although a brush with soft bristles would work as well. Remember of course to put the gas logs back exactly as they were, or refer to the manufacturer’s manual. Improper log placement will lead to incomplete combustion and all of its associated risks.