Modern Cameras have sensor cleaning automatically (done by fast shaking). However you can still get dirt on your sensor which wont shift with shaking and might require a moist clean. We use the kind of cleaner where you slide fabric (called a swab) over the sensor using eclipse fluid. Although you can use a size smaller than the sensor and pull it across a few times it is recommended that you get one which fits your sensor width, so they come in 3 sizes. The problem is that it can be very difficult to work out which size is right …