Hello Cleaning_joy, and Welcome to Mrs. Clean’s Forum:
As you have found, the biggest challenge in keeping brass shiny is to not only remove the tarnish, but delay the oxidation process. What is recommended is a weekly wiping with a little liquid ammonia on a soft cloth to help keep unlacquered brass shiny.
Most brass polishes such as "Brasso®," "Never Dull®," etc. coat the copper surface with a thin film of oil to help inhibit future tarnishing. I don’t know what you are using as a polish but check to make sure that it contains all of the following:
1. A solvent/detergent to remove tarnish
2. A mild abrasive to polish the meta
3. An oil to act as a barrier between the raw metal and air
Be sure not to overcoat your brass. More is not better in this case as excess polish creates a smudging problem and will only attract dirt and grime. Only a very small amount should be applied; just enough to create a thin film.
Some recommend distributing a small an amount of polish on an absorbent cloth. Then, dry the cloth for a minimum of 24 hours. After 24 hours, polish object using a motion “with the grain”. Working in small sections, use another clean cloth to buff in a rapid motion. This will create friction and harden the polish creating a surface that will be harder for dirt to stick to.
I also found this interesting piece of advice: Use Olive Oil to keep brass looking brighter and it will require less polishing. Olive oil is said to retard the oxidation process.
If you want to lacquer, it can be done at home or you can have it done for you. From what I have found, it can be a tricky process to do it yourself. First, all old lacquer (if it was lacquered) must be removed and the surface completely clean. This means that no fingerprints or cleaner whatsoever remain. Spray the lacquer on evenly and use multiple thin coats. Most people say that is not easy to do the first time. To maintain the lacquer finish, wash in sudsy, lukewarm water, rinse and dry. Never use hot water on lacquered items because it will degrade the lacquer; and do not polish or soak in water after lacquer is applied.
Here's some more information about
brass cleaning.
I hope this helps and good luck with your project. Let us know how it all works out!