What are you polishing, Rick? Are they sand cast brass parts? Do they already have a smooth finish or are they rough? If they have a nice smooth finish that was polished at one time and you just want to bring back the polish, you can do it with Tarnex but that will give you a so-so polish. You can get most of the old tarnish off with that stuff but to bring back a nice bright polish, it will take some elbow grease and some brass polish like Brass-O or Never Dull. I keep a can of Never Dull on hand for all metal polishing. It is a cotton fiber material that you just pull off a piece and start rubbing. I think it works great. Another possibility is jewler's rouge and some felt polishing tips and wheels for a Dremmel tool, if you have one.
If you are starting with sand castings, they will require a good bit of file work and then a series of grits of emery paper. I use fine mill bastard files. You will need both a flat file and a round file. It helps if you have some chalk to rub on your files to keep the teeth from filling up with filings. A file card or wire brush will be needed to keep the teeth clean and cutting nicely. Do not let the teeth fill up or you will eventually get enough metal stuck in the teeth of your file to cause it to scratch your work. Once you get the file work done to your satisfaction, tear the emery paper into usable strips and use it like shining shoes to work your brass. Or you can wrap pieces around a dowel or flat stick. Keep changing your emery paper as it wears down and when you need to, change to the next finer grit. Keep working to finer and finer grits until you have a polished surface. At that point, it is time for the jewler's rouge and the Dremmel tool for the final polish.
PM me if you need any more help, old buddy.
Bill