Cleaning dust from the phone's interior

My phone (Torch 9810) regularly gets exposed to cement and concrete dust, and when this fine dust gets inside, the sound quality plummets. Unfortunately, this dust is not magnetic, so it won't come out if I wave a magnet around. Is it possible to open up the phone behind the battery compartment in order to clean it? Am I better off paying to have it done?

I'm afraid to vacuum because I've heard horror stories about electronic devices being destroyed by static electricity. Any advice would be very appreciated.

This seems to affect only the speaker. I've never had dust get behind the screen.