I use a Nikon D7100 I spotted stains in the sky, shooting on a blank sheet F16 confirmed and indicated other spots (off autofocus). I used the auto sensor cleaning and blow that proved ineffective in this case stains that can be dust bonded by static electricity or grease stains caused by the mechanism. There is no risk if you respect the user manual (put 3 or 4 drops) battery fully loaded .. We must support enough (at the beginning are afraid), pressing the stick a little down, it is very flexible for that. In this case it took me two sticks. I recommend it!
