I don't want to get into an argument over minor points, but...

I'm a non-smoker, and have never lived in an unusually dusty environment.
I'm sure I'm hardly alone in //never// having had to clean an optical-disk
player. (This includes two LV machines, two DVD players, one Blu-ray player,
an SACD player, multiple computer drives, and I-don't-know-how-many CD
players, including portables.)

I agree that cigarette smoke and cooking vapors (especially oils) are the
most-likely cause of a dirty lens. They get there because they settle on --
then stick to -- the lens. Plain dust doesn't stick to the lens, so it can
be blown away when the disk spins.

A moving surface drags air with it. (This is why dust tends to settle in
corners -- there's no air motion at those surfaces.) This moving air should
have //some// effect on non-sticky dust. I believe Geneva (Nortronics) made
a faux CD with shallow vanes on the surface to increase the air motion. (It
should be in the garage. I'll look for it.)

In my opinion, a regularly used optical-disk player is not going to
accumulate much, if any, plain dust on its lens. I remain to be convinced
otherwise.

Another point -- has does /any/ contaminant get on the surface of the lens?
If you argue that it's pulled in by the spinning disk, then... Well, you
draw the conclusion.

* As far as I know, the optical system in most optical-disk players is a
sealed unit.