The Cleaning Set I found by chance and I found no negative review I have ordered me. The instructions on the net was pretty easy.
Before cleaning, I then shot nor a "before" picture. Set Maximum land aperture (f16), then the stains come out very clearly (see photo above). With the D7000, the menu item "Camera Inspection" allows permanent the mirror moves and thus free rein to the sensor. A drop in the wiper is sufficient. The wipers are as wide as the APS-C sensor. (Between by turning wiper) two times from left to right wiped mirror back down (by turning off the camera) and the lens back on it. The "after" photo brought security - clean everything. The whole thing took less than 5 minutes and a "fumbling" it was not.
3 of 4 wipers are left and the liquid should also rich. So well put away and the next time cleaning they are certainly back in the game.