A bulb blower is just a hand-sized rubber bladder that you squeeze. It directs a low pressure stream of air from a nozzle. It has a filter in it so that dust is removed when it fills. Your camera will have setting (to be used with full battery only) that locks the shutter open exposing the sensor. You activate this, then, with the blower completely OUTSIDE the camera, direct a few puffs at the sensor surface. I do this with the camera held so the sensor is facing downward so nothing can fall inside. This will remove dust. It won't remove anything sticky. If it doesn't work then you have the options to physically clean the sensor (strictly the filter in front of the sensor) or pay someone to do it. Everyone should have a bulb-blower anyway as a first step in lens cleaning, to remove dust/grit. Don't confuse a bulb-blower wih a blower brush. The latter tend to be no good at blowing and rely on the brush for lens cleaning. You can also remove some dust by firing the camera (with a lens on) at maximum burst mode. The mirror going up and down will make a draught which can clean the sensor. Cameras have sticky surfaces inside to which loose dust is supposed to stick. I tend to set the camera self-clean option to operate both when camera powers up and powers down. I always (nearly) change lenses with the camera powered off and only if I'm in a sheltered place with sufficient free hands to cope with getting the lens caps on and off and can do the change as quickly as possible.