I would like to clean the ducts in my house (1966 ranch; 1400 sq ft
main level - floor registers, 1200 sq ft basement - ceiling registers;
Denver metro.) Nothing _terribly_ wrong with the air flow, but a couple
of the registers are producing mediocre air flow, so I just want to
make sure and do some duct cleaning.
I should add that this is not an issue of anyone in the house suffering
from allergies or anything like that. Just trying to improve the air
flow to make the whole heating/cooling system more efficient.

I've read several threads on this discussion group, and it sound like I
should avoid duct cleaning services, which usually are not worth the
price they are charging. So I'm thinking of getting a shop vac and
cleaning the ducts myself - just push in the shop vac hose as deep as I
can and try to vacuum all the junk.

I'm pretty new to this, so is there a specific shop-vas
type/model/brand that you would recommend for this type of job?
Note: the narrowest vent openings are 1 3/8 - 1.5 in.

I'll appreciate any helpful pointers.
No flames/sarcasm, please

Cheers,
Bubba