I use the Lenspen SensorKlear pen and it works well and reasonably priced. I got mine in a kit with 3 spare cleaning tips/caps. Each is claimed to last about 50 cleans and at the rate I am going that should last me close to the 22nd century.
You get rid of all the crap first by holding the camera sensor down, and blow out the loose crap with a decent rocket blower
With the camera facing down, run through several cycles of the cameras sensor cleaning thingie (with the Olympus cameras that just means power it on and off a couple of times). That will dislodge any loose stuff that the blower didn't get (there shouldn't be any).
Then work your magic with the SensorKlear pen.
I have never had a situation where the SensorKlear didn't work and no need for wet cleaning.