Metals will age with time beautifully like us into patinas no matter how many coats of lacquer you apply. Learn to love this natural phenomena.
Polish brass/copper objects with Bras-so/Dara allied polishing liquid.Gently rubbing it in, letting it dry and thoroughly rubbing it off all with a non abrasive soft cloth.Repeat process till you like the resulting colour or tarnished spots vanish. You can also use traditional solutions like rubbing tamarind paste gently over the surface.
For a more non yellow shine apply a tooth-powder in a dry or paste format in a similar fashion.
For antique and patina finishes apply a coat of wax polish on the object to protect it.