I didn't include a tumbler in my origonal set up...but after just a few weeks I ordered one.
It's SO easy and since I've now taken to scrounging brass, I like to toss it all in the tumbler and sort/inspect it after it's clean.
Whatever you do, just make sure you make provisions to avoid lead exposure.
Here's some "home brew" recipes for chemical cleaning I pulled off the web.
I haven't used any of them so can't speak for results......
In the long run, I'm not sure chemical cleaning, even with home brew won't wind up costing you more...
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Chemical Case Cleaning Solutions
While tumbling cases in an abrasive media provides the best finish, extremely dirty cases can be decapped first (using a non-sizing die) and then washed in one of the following solutions. The final rinse in soapy water helps prevent tarnishing. All of these methods were approved by Frankford Arsenal and will not weaken your brass.
• A 5 percent solution of citric acid (available from your drugstore) and warm water for about 10 minutes. If your water is very hard increase the amount of citric acid. You can add some Dawn™ or Cascade™ dishwasher liquid soap (which does not contain ammonia--be careful some do), to the solution for extra grease cutting ability. Follow with a rinse in hot soapy water (Ivory™ works well) and allow to dry.
• A solution of 1 quart of white vinegar and 2 tablespoons of salt. Soak with some agitation for 15 to 20 minutes and follow with a rinse of soapy hot water and allow to dry.
• A solution of 1 quart of water, 1 cup white vinegar, 1/2 cup lemon juice, 1/4 cup laundry or dishwashing detergent, 1/8 cup salt. Soak with some agitation for 15 to 20 minutes and follow with a rinse of soapy hot water and allow to dry. This may leave brass with a slight pinkish cast which will disappear with a short tumble in media.
• Military arsenals use a heated 4 percent sulfuric acid dip with a little potassium dichromate added. The solution is heated until bubbles rise slowly without it boiling and the cases are dipped into it for 4 -5 minutes using a basket of copper screening or plastic. A final rinse using plain hot water is followed by hot water with Ivory™ soap in it and the cases are left to drain and dry. Because of the use of heated sulfuric acid this method is probably impractical for home use but is given here to show what can be safely used.
Cases which have been fired several times and which show signs of carbon build up internally can be rinsed in straight paint & varnish makers (P&VM) naphtha available at any paint store. Decap, soak for 5 - 10 minutes, drain, allow to air dry and then tumble as usual. Cases will be sparkling clean inside and out but not any shinier.