We have brass tables at our company that we rent out for parties, but when we get them back they are often covered in stains from spilt drinks which we can never seem to remove. Brasso helps but doesn't clean off the problem. Is there something else we could try to get them clean and bring them back to their gleaming best.
I seem to remember that many years ago, some cola had been spilt on a copper topped table. It wasn't cleaned up until the morning and had cleaned the copper where it was spilt. Maybe it will have the same effect on brass?
Try plumbers soldering flux, works instantly if heated but must be thoroughly washed off after or it will go green! Polish with Brasso as normal. You could get them proffessionally cleaned and lacquered to save a lot of work.