Gonna watch this thread. I have also been thinking about getting into Chimney cleaning. I use a "truckmaster" to do air ducts. I really wonder if I could use that inside a chimney. They make pretty large brushes.
I did it for 5 years. It's good money. In my area you can do $160 an hour but it's only busy October-March, then nobody thinks about it unless birds or squirrels get in. 99% of them can be cleaned from the bottom. You want to be inside anyways to make sure the vacuum is sucking the dust out of the air. Otherwise you could fill up Mrs. Pilfs house with dust.