Air ducts which are connected to those air vents are a prime location for gathering dirt, dust, and germs. You can do this job yourself if you purchase the right tools but let me tell you, it is well worth hiring a team of professionals. I had this done in my home about 6 months ago and I was amazed at what I saw coming out of our air ducts. The professionals have all the right tools and a commercial vacuum to suck up any residual gunk that falls out of the ducts. I had to do a little vacuuming once they were done but I felt like I was breathing much cleaner air. Check online for discount coupons to have this service provided in your home. - See more at: http://www.quickanddirtytips.com/house-home/housekeeping/14-places-where-dirt-hides-in-your-home#sthash.kqgkudm8.dpuf