Here is a good used alternator that was in my wife's car. The idiot electrician who installed it had dropped it and caused the pulley to be damaged but put it in the car anyway. The damaged Pulley caused the belt to be destroyed really fast. We got another alternator installed but this one is perfectly good except for the pulley.
Here is how I removed the pulley.
Step 1: The Tools.
A torx socket, 3/8inch Ratchet and a 24mm (or 15/16") spanner.
Step 2: Applying the Tools.
An easy enough counterclockwise turn while holding the shaft with the Ratchet and the nut came loose.
Step 3: Removing the Pulley.
The nut unscrews and the pulley slides out. Can't get any easier than that!
Step 4: The Bogus Pulley.
Here you see the damaged area thanks to that jackarse auto electrician. In the future I will do the replacement of her alternator.