Corroded Wheels!??

[SOP8920@Siena.edu]

Hi folks,
   I was gone for 11 days, and upon my return I found that my tires where
rather low on air. I took the Q out, and filled up the low tires. The next day,
the RF was flat and the RR was 1/2 way there. I pumped up the tires and drove
the car to where I purchased the tires. 
   The monkey-lads working the counter took my car in and checked out the
tires. When I picked it up, they said that they removed the tires from the
wheels and discovered that "corrosion" was causing the beads to not seal
properly. I said.. "huh"? He said that my wheels were old, paint peeling, etc,
and that there was some corrosion inside the wheel that was preventing proper
sealing. He said he cleaned things up a bit, then remounted the tires using the
bead-sealer stuff. He said that if they started to deflate again, I might need
to have the wheels professionally serviced. 
    I've never heard of this before! I've got an old shit-box at home whose
steel wheels have a nice layer of rust on them. They seem to seal fine.
Furthermore, these wheels are a Aluminum alloy.. right? Aluminum will oxidize,
but the thin layer of oxidation will coat it and prevent any further oxidation.
That's why old aluminum gets that white film on it. What the heck is he talking
about? 
    P.S. To those who kindly responded to my post about RV purchases, I'll be
getting back to that shortly. Things are currently in the works, and I'll reply
to you all shortly. 
                               -Osman Parvez
                                89 200q (150K miles)
                                Siena College
                                Albany NY