Canaduct Duct Cleaning

My first question was can I show you the vents so you can cover them? I was told that was not necessary as they had state of the art equipment and only companies with older equipment cover the vents...I can't say I was thrilled to spend the amount of time I did vacumming my house after they left (not expecting it) but once Paul explained to me why it happened (surface dirt at the top of the ducts using a pressurized spray to blow it down to the main vacume to have it suctioned up does make sense. Either way I'm confident they are clean and the sanization smells like heaven when the furnace kicks in. Did I mention polite/courteous and they genuinely seem to care about customer service which is a nice change from indifference.