I've had good luck using a similar kit from this company on my GH2 (see link below). I think you're supposed to start with least amount of contact first such as air blower, and work your way up to more "invasive" techniques such as this kit. You can also take camera to camera store to have cleaned, but I'd make sure they're solid company with care and attention to detail.
http://www.bhphotovideo.com/c/product/1165579-REG/photographic_solutions_ultra_swab_type_3.html
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