I do. I need to advertise it more. I charge $100-125 for a cleaning but that includes the vent and taking off enough of the outer shell and airpath guard to clean out the inside, motor, airpath and fan squirrel cage. It takes 1 hour to 1.5 hour start to finish. I don't mess with gas dryers but I will clean vent only for $50. Vent only is quick and easy.
The appliance repair guys here do not offer vent cleaning so I get considerable business just giving them business cards. They'd rather send me the business than mess with it. The really good vent money for me is summertime college fraternities. As long as I have a master key I can bang them out all day long fast with a helper.
We charge $150 and get almost all of the calls converted to jobs. Like others here we are highly recommended com heating companies and appliance repair companies. Anytime we are referred we almost always get the job.
I don't do nearly as many as I used to and some are a true pain to do. Most associations have rules as to who can clean. Many of the vents are hidden in walls or ceilings, poorly constructed and/or made of flexible vinyl (silver or white) or PVC which is a code violation (the material the vent pipe is made of must be able to contain a fire not add to it) All joints should be sealed with foil tape, not duct tape and screws are not permitted. Many contractors don't bother sealing the joints and if you knock the vent apart in the wall you likely own it which means its up to you to fix it and building managers expect that done for free. Some are buried under decks or vented into attics, both of which are code violations. All birds are protected under the Federal Migratory Bird Act and if the vent contains a nest with eggs or young, you cannot legally do anything to harm them and the fine is in the thousands if you get turned in!