Is anyone aware of a way to prevent this, i have just exchanged my 6s due to this and would like to prevent it happening to this one, is there a way to stop it or is it just how it is?
If you really believe dust is entering via the switch put a piece of tape over the switch. If you trim it nicely it will seal the open off and would be a nice test to see if "dust" is really entering there. I still have not seen any proof that the particles are dust.