Why dust entered into my Lumia 720 front facing camera?

[Windows Central Question]

I purchased Lumia 720 in Dec 2013.
At that time I have noticed some spots on the Secondary or front facing camera. I thought its just a design.

But now the front/Secondary camera was completely covered with fine dust. I hardly get my face using front camera.

How do it get rectified?

 

[gooeyphlegm]

You can always find a how to disassemble videos and clean it yourself

 

[FredBloggs007]

Was a common problem with the 920 too. Possible design flaw?