mvette , I can tell you how I polished mine. I took and put the pulley on a brake lathe and while it was turning I used an orbital sander to sand down the rough casting. After the pulley was half way smooth I then used an bench grinder with a 6 inch buffer wheel (can be purchased at sears) along with rouge that can be purchased at sears and put the final polish on it.
mvette I am sure it can be done by hand the lathe just makes it much faster and easier to get to the inside edge. I started mine by hand and did 50% of it that way before I tried it on the lathe. Make sure to tape up your brg before you start to keep water and grit out of it.