I guess I've just been lucky.
I don't give my Toucam any special treatment (like locking it in dustproof cases etc) and for over 12 months it has been dropped several times, accidentally left on the table overnight a few times (unprotected) carted around to Camps and club nights in a cardboard box of bits, wringing wet when left in the rain a few times
, and when I'm not carting it about, it lives outside in the scope, which is most of the time.
I don't use a cover on it, and yet I still don't have one speck of dust on the chip!
And we get a LOT of dust around here with all the dirt roads and windblown paddocks!!!
And yet I get a lot of dust on my EP's when they sit outside the EP case for a few hours.
Wierd but lucky.