Hi. We moved into a 45 year old home last summer. It has gas heat and central A/C. I doubt the vents have ever been cleaned.

Is there a method to cleaning vents that can be done by the homeowner or does it need to be cleaned by a professional?

You really need the equipment (long brushes and suction) that the professionals use for duct cleaning.

Check with Sears; I see coupons from them in the mail every week. Around here, a whole house duct cleaning runs 200-250... and if it's never been done in your home before, you'll notice and love the results.