If your brass is very dirty, first use a liquid brass cleaner to take off the worst.
For polishing, you use a vibratory tumbler. A rotary tumbler may be used but I have no experience using it so you'll need to adjust the time (longer). Always keep notes.
To your tumbler barrell, add a few cups of walnut shell and a half teaspoon of red rouge. Run for a few minutes to allow the rouge to coat the shell. You will want the shell to be coated with rouge but not coated too thickly, so you may need to add a little more but just a little at a time! Once you feel the media is right, add your brass and run for a few minutes. Keep your eye on it; brass is softer than walnut and you don't want to lose metal, you just want to polish the metal. Your brass should be beautifully shined.
The media is reusable for a long time. Store it in a covered container. You can add more rouge and won't need to dump out the walnut until it is very dirty. You can also add a couple of teaspoons of mineral spirits and run for a while to clean the walnut up before adding the rouge.
Tumbling Glass / Sea Glass
My customers tumble their glass according to the rock tumbling instructions. For thinner pieces some pellets will be necessary for cushioning, but all in all just tumble as you would any delicate stone such as obsidian. You may or may not polish, depending on the look you are after. If you want a polish you will use cerium oxide or M-5.