Not worth worrying about, it won't affect images. Eventually you'll have specks on your sensor.....I suggest you have a professional cleaning done at that point. No need to send it to Canon for a cleaning, any camera repair shop can do it, I'd suggest asking a local photo supply shop who they recommend. It isn't hard to do the job right when using the right tools. Eyeglass cloths and eyeglass cleaner are not the right tools. The only thing they are good for is removing a fingerprint....only because short of breakage, a fingerprint is the worst thing you can do to an optic. Worse than dust, chips or scratches. I clean my own gear (cameras, lenses, telescopes), but then I used to do it for a living on equipment that cost the taxpayers far more than cameras. Relax and keep shooting.