We don’t often see this amount of creosote anymore. Modern, efficient appliances and better burning practices have largely eliminated flue blockages as the one we see in this photo. Our technician had to use a hammer and chisel to make a hole big enough to allow a brush to fit into the flue in order to sweep it. In this case, a “perfect storm” combination of wet wood, excessively large pieces of wood and smothered fires (caused by the air inlet control being closed too much) created this blockage.
Hopefully, we have convinced this customer to split the wood into smaller pieces, put less wood in the stove and leave the air inlet open more.