Ko.Fe.
Lenses 35/21 Gears 46/20
How difficult and risky depends on how capable you are. Some are ending with sensor scratching.
Is this one looks difficult?
http://www.lupico.com/articles/sensor-cleaning-for-the-brave-at-heart-do-it-yourself-without-fear/
Is this one looks difficult?
http://www.lupico.com/articles/sensor-cleaning-for-the-brave-at-heart-do-it-yourself-without-fear/