Tonight I noticed my T1i has a pretty big speck of dust or something in the lower right corner of the viewfinder. I initially thought it was on the sensor, but when I take a photo, the speck doesn't show up in the photograph. I tried wiping the viewfinder to clean off any dust, but the speck is still there. Is it possible for something to be on the inside of the viewfinder? How would this happen and how can I get it off. Since it doesn't affect the quality of the photos, I'm not overly concerned about this, but it is pretty annoying.