A lot of people swear by the Scotchbrite disks on a bench grinder. Instead, I use files, a small assortment of flat mill files, a Vixen file and several small shaped files for the inside corners and so on. I've seen the very fine debris left in the air by both sanders and the Scotchbrite disks. Can't see the stuff unless it's in strong direct sunlight. Please use a good dust mask or an N95 mask while using these tools.
Incidentally, a belt sander of some kind can be very useful on edges - try to keep the sandpaper movement parallel to the edge for the smoothest results. I have two, one is a 12" disk and the other is this 1" belt sander.
It's definitely worth the money.
On some parts that I needed to cut with a bandsaw, I follow that with the sander and then a Vixen file, with the mill or other files to smooth out the corners of the edge.