After probably more than 1,000 lens changes in the field during my long photography road trip, I noticed that sensor spots were becoming an issue during my post processing. I've more or less given up on attempting to wet clean my own sensor. Instead, I've used the Sensor Gel stick over the past couple of years to clean the sensor on my Nikon D800.
Here's how my sensor looked after returning from the trip:
It looks like a complete mess. In reality, it's not nearly as bad as it appears. More spots are visible at small apertures. So, when cleaning the sensor, I shoot at f/16 against a uniform, white background (my computer monitor). If I were to shoot at a wider aperture, which I almost always do in the field, not nearly as many spots are visible. Also, within Lightroom's "Visualize Spots" feature, the slider can be moved from left to right to adjust the tolerance of the view. In the shot above, the slider was set to the most extreme setting--making everything visible.
In an attempt to clean the sensor, the first thing that I did was to activate the automatic sensor cleaning option on the Nikon D800. That usually helps, but doesn't always take care of all the dust. The next thing I tried was to blow the particles from the sensor using a rocket air blower. Finally, I took a minute to apply the Sensor Gel stick to the sensor. Here's the result:
That's much better! But, those few spots remaining spots still bothered me, so I tried again:
This attempt is That's slightly better, but notice that while some of the spots are removed, new ones have appeared. That's what tends to happen to me as I keep trying to clean the sensor--it sometimes doesn't get any better. Sometimes it gets worse!
So, I lowered the tolerance setting on the sensor spot view in Lightroom to a more reasonable level. I think the sensor is clean enough for me for the time being. Thankfully, there's no need for me to take the camera into APS to have the sensor wet cleaned.
Note that the "Visualize Spots" box is checked (bottom of picture) and that the slider was moved slightly left from the right edge of the range. This feature appears in the Develop Module when using the Spot Removal Tool.
While it won't clean everything that might stick to a sensor, the Sensor Gel stick is easy to use and has done the job for several sensor cleanings for me. It's not cheap, but certainly a lot less expensive than taking the camera in to have the sensor cleaned. The breakeven point is under two cleanings.