Chances exist that lint that has in fact been restricting the exhaust vent over a prolonged time period can cause overheating which in turn can cause a fire. The establish of lint that occurs over a prolonged amount of time is not merely a fire threat, it is also a clothing dryer problem that gradually steals the energy efficiency of the clothes dryer and gradually cost you significantly more money.
"This a very professional company that came the next day after being contacted late in the day prior. The two guys that came to the door that did the work were well dressed and very courteous. They cleaned my diver vent and it works perfectly. I have their literature and will be calling them when I m ready for duct cleaning. Nice equipment too! Thanks for the good work. Nice not to have scroungy guys showing up at the door. "