What you have is 2 oil spots and 2 dust spots. You don't have to clean your whole sensor to get rid of these spots. Just get yourself a magnifying glass and Sensor Klear pen from the same company that makes lens pens. Magnifying glass will let you see where spots are and use Sensor Klear pen to flick them off. BTW, Sensor Klear pen and Lens Pen are not the same thing. Lens Pen uses very fine carbon to clean lenses. Sensor Klear uses nothing but very soft felt.