When the drive is not in use, is there any internal barrier that seals the drive off from the outside world? Or is it just the small fabric flaps that prevent dust from entering? I find it hard to believe there is nothing sealing the drive - I figure the barrier retracts when the sensors at the edge of the drive pick up a disc being inserted. But I can't seem to find any information about this, so I'm not sure.
I normally use compressed air to keep dust off my electronics, but I had a little accident the other night. I was cleaning the gray fabric flaps that cover the DVD slot on the Wii, when I slightly angled the compressed air can and some of it discharged in fluid form - right into the slot. The Wii was off, and the spray was fairly small, but still not a good thing at all.
I left the Wii off for a few days to ensure that anything that might have gotten in there was dried, and then tried it. It appears to work fine, and the couple of discs I played worked fine and came out without any marks on them or anything. However, I'm kind of paranoid in general, and I'd feel much better if there was a barrier, as that would mean any compressed air discharge would have just hit that, and not entered the internal mechanics and lens of the drive.