The brass taps are almost certain to be lacquered to prevent tarnishing. If you clean them aggresively, or user a polish, you will take the laquer off and they will quickly tarnish and need much more polishing. The tap makers usually say use a soft cloth and a drop of WUL
If the scale is round the tip of the spout, look carefully, there will probably be a screw-in plastic diffuser that the limescale is on. You can unscrew this and put it in a jar with descaler.
If the limescale is round the spindle under the knob, the gland is worn and needs tightening or resealing. This needs basic plumbing skills and tools.