Use air in a can designed for cameras/electronics aka air duster Eric. Hold the can upright and give is a quick burst to clear nozzle of any liquid propellant, then keep it upright a quick burst about 150mm away from the sensor. If the dust still sticks use a sensor swab or get a sensor brush, i use make-up applicators which are of very soft foam for oils and stubberen dust and lightly sweep it off. This method maybe wrong but lol i don't own a $7k camera, and i have never left any scratches in any of my sensors. If you google dslr lens/sensor cleaning you will find a ton of info and methods.
With your camera and low res how about making a mosaic out of highly magnified images. Turning the gain down will help out with noise and you can increase exposure to compensate. Lol i'am far from being an expert and would say of novice if that
1 more thing is to check out your codec and that your using a lossless, this will give you the best image possible. If your using a compression codec then you will pull higher fps but the images are like jpeg vs raw/tiff. If the seeing is bad by that i mean air turbulence drop back the res and crack the FPS up, it will give you a chance to get some clear shoots in the avi though more gain maybe needed.
Lol things never go right first time around haha, gl to your next session and do some googling on your dmk41 to get others tips and wisdom.