I picked up an Eastwood Vibratory Tumbler to restore the parts on the GS. Very happy with the results. It takes awhile though. It is a two part system. The first stage is to run the parts with a batch of green rust cutting cubes. Did this for about 8 hours. The second stage is to run the parts with a batch of Dry Shine Media for about 24 hours.
Here is the tumbler and some comparison photos.