I have washed paper filters off lawnmowers in solvent to remove greasy/oily residue from outside then blown dry with no ill effects to the filter. I wouldn't recommend doing that on a high dollar tractor engine though as the filters are readily available and usually less than $30.
Recommended way to clean per my owners manual is to lightly bump the filter on the tractor tire while rotating it to dislodge loose dust particles. Blowing out with low pressure air (60PSI or so) is also recommended but don't get the nozzle too close to the paper. I bump mine to get out most of the dust, then blow with air. I angle the air nozzle at 45 degrees to the outside of the filter to blow out the major dust particles, then work the inside using the same method. I have never damaged on yet. Don't mess with the inside filter (if your tractor has one) unless it is dirty. If it has dirt/dust on it, that means your external filter is bad and you need to replace both filters.
My Manual recommends replacement yearly but I don't replace mine unless the outside is black & dirty, but I don't put that many hours per year on my tractors. Even on our farm tractors with a thousand hours per year, we didn't replace the filter unless it was damaged, just cleaned them daily. As long as the engine isn't starving for air and the filter is not leaking there really isn't a need to change it out on a yearly basis.
Cleaning periodically (every 10 hours in dust conditions and weekly in normal ) will make it last a long time as long as you are careful and don't damage the paper element.
