Ok, I'm a little late to this party, but I have been handloading brass for about 15 years, and there are several ways to get the oxidation off of brass. I use a vibrating cleaner setup with ground corn cob or walnut shells as the cleaning media. It can be reused several times before it has collected too much material to work well. I have also read of others that put it in a mesh bag and run it through a front-load washing machine with a little detergent, and allow the metal on metal contact to clean the cases up. Of course, it depends on the amount of brass we are talking about here. Since you are probably dealing with large quantities, an industrial rotating dryer (for polymers and the like) loaded with about a 4:1 media/brass ratio and then screened to remove the media afterwards could work. I have also had good luck using a little automotive wax in the media, it helps shine the brass and also leaves a thin coating of wax that aids in resizing and also helps to keep the brass from oxidizing during storage.
Matt
Quality, quantity, cost. Pick two.