Any chance I can clean out my own oil furnace?

The oil burning forced air furnace starts right and burns with a
well-shaped flame, but it hasn't been vacuumed for a season and a
half, and I would like to do it myself if I can.

I found 5 upright vacuum cleaners in the trash, and usually I just
unclog them and give them to Goodwill. These, however, were I think
thrown away by a maid who was going out of business, or one who bought
a whole bunch of new tools. Only one at most could be fixed cheaply,
but 2 of the other 4 have hoses on them.

I wouuld either use my shop-Vac, or one of these vacuum cleaners.

Probably best to use the junk vaccum?? If I burned it up, no loss,
if I didn't I could save it for next year. The Hoover has a 12 amp
motor.

The hose isn't that long, so I would use a piece of pipe and some tape
to temporarily join a couple hoses in series.

Would it be better to take off the belt that drives the brush? I
think it would spin faster then and have more suction. Or might the
motor spin too fast??


But frankly, the Hoover upright with hose confuses me. It's a typical
upright, but bagless, and has a hose attachment on the side by the
right rear wheel. The hose winds around and goes into the back. When
the hose is connected tothe vacuum at both ends, I don't know if any
dirt goes through the hose or not. BUT WHEN it is disconected at the
bottom and the upholstery attachment attached there, I don't know what
would cause there to be suction into the bag. The motor is near the
floor. How is it supposed to work? I have a general desire to
understand this -- I've sort of wondered for years -- not just related
to the furnace.