Chosen Solution

how do i get rid of the dust accumulated behind the glass that protects the lens of the camera (rear camera)

Here an dissamble instruction manual http://depositfiles.com/files/o623sfz2r Use the “Samsung GT-I9100 Galaxy S II - 07 Level 2 repair - disassembly.pdf” to dissamble. You have just to unscrew the 7 silver screws behind your phone, and to dispart the back-cover of your phone. No need to dissasmble your mother board. Don’t us any liquid, just use a dry cloth for clean-up

put it in soapwater later on dry it in the sun it will be brand new