Air Bag Corrosion?

Assuming you’re absolutely sure you didn’t do anything that would cause it and you sure that it actually will affect the operation of the air bag, then why not? Go for it.

 

“Cold moist air from the AC”? Perhaps I’m misinformed, but I was taught AC units actually dehumidify air. IF that is true, your theory doesn’t hold water (pun intended).
But if you believe it, go for it. NTSA might find your theory interesting.

 

I can think of a situation where condensation may occur. The humidity in Ohio is generally fairly high especially if you're near the Ohio river. Say you take a drive and use your A/C. At some point the interior of the vehicle will be cool, dry, and comfortable. When nearing the end of your drive, and as a preventative measure, you turn off the A/C compressor, cycle the airflow mode to outside air, and bump up the fan speed some. This will initially increase the water condensate on the A/C evaporator core, acting to rinse the unit and flush the drainage system. Then it will do some drying of the inside of the air handler box. This will usually prevent mold/mildew smells from developing in the air handler box. But it will also raise the humidity back up inside the vehicle. Any bare metal that has been cooled with A/C airflow will condense this humidity and rust may eventually result. I would be hesitant to do anything myself to clean up the rust, given the explosive function of the air bag system. Maybe show it to a Toyota service writer and see what they say.