Smell from air vents 99 Accord EX

I have this strange dusty smell coming from the air vents. However I
get it when I set the blower to take air from the outside. It goes
away if I set it for recirculation. It is less noticable when I turn
the AC on.
I tried spraying Lysol into air intake openings, replaced micron
filters (first thing), tried running hot air for a while.

 

I had this same problem and the Honda dealerships's mechanic removed
something and cleaned it and put it back. I don't remember the cost. You
might set the blower to take air from the outside for a couple of weeks
except when it is humid or wet or raining. Run it to take air from the
outside only in the day time when it is fairly hot out side the car. In
other words, the dry air from outside should dry out the inner workings of
the airn conditioner. Any humid or wet air makes the problem worse so set
it for recirculation on those days. More Lysol may also help.

 

I've used (with success) a product from Wynn's called Fresh Air. You might
want to try that, as an alternative to Lysol.