haha, lfmracing you should have specified what you actually bought. Lenspen is the brand, which offers both "lens pen" and "sensor pen".


Regarding the sensor pen, I didn't notice it leaves carbon residue (maybe I didn't test). I have applied it in sensor cleaning several times. I guess what you need to make sure to do is after cleaning with the sensor pen, use the blower to give some good burst of air to the sensor area WHILE keeping the lens mount facing down (so the carbon residues, if any will be blown out and fall down)


I have another "lens pen", I do notice they leave black residue, because I used lens cloth to wipe the front glass after the "lens pen" is applied. I think this carbon thingy is the material that helps absorb oils from fingerprints.


Albeit so, I am still reluctant to use the brush part of "lens pen" on the front glass cuz it does not seem so soft that it would scratch the surface...ok I admit I am a little paranoid.