Brasso cleaner will shine brass up nicely.
Yes, clean up and polish it, then spray on clear polyurethane.
Brasso is the product of choice, you can find it at DIY stores.
Hi Mary, Rinse with warm water and dry thoroughly. For tougher cleaning jobs, pull out the ketchup, tomato sauce, or tomato paste. Simply rub a thin coat onto the brass, let sit for an hour or so, and then clean the piece with hot, soapy water. Another option is to make a paste of equal parts salt, flour, and white vinegar.
Brass gets a film on it so Brasso is a good product to use without damaging the surface. Once the film comes off it will shine if it had a shiny finish before.