You should drain the compressor tank after you use it. That prevents the water from accumulating and corroding the inside. It still doesn't change the fact that compressing air creates water vapor condensation as a by product, which is why you should use an inline moisture trap. At the very least, one like this
https://harborfreight.com/inline-desiccant-dryerfilter-64637.htmlI prefer to use a DataVac which is specifically made to dust electronics. It's also much more portable and convenient than using an air compressor and waiting for the tank to fill. If you're looking for something quiet, the DataVac isn't it. The motor is pretty powerful and loud.
Also when blowing out the fans be sure to not just let them spin freely. You can easily overspin and damage the mechanism. I like to use a detailing brush to lightly brush the underside of the fans to loosen the dust before blowing out one fan at a time while keeping a finger in between the blade to prevent it from spinning.