Charlie, yes you can sand it back, and the Micro Mark sanding/polishing system mentioned above will work great. You can also lightly use oooo steel wool, just make sure you clean it up by rinsing the part under cold water after you're done. Now, as for the reason for this problem-- you used to heavy a coat as mentioned above also-- a frequent problem when using spray-can paints, especially hardware store varieties like Krylon. These paints are made for large area coverage, and are difficult to control, But there is a simple solution-- which I highly recommend, simply decant the paint into another container and use it in your airbrush. This will give you more control of the paint, and produce a finer spray pattern.
VR Russ