depends how heavy it is and how patient you are. If its really heavy then I have given it smart taps with the kind of light hammer that you use for hanging pictures, this can chip off the limescale without denting the metal, but keep in mind that there might already be damage to the metal under the limescale. vinegar or lemon juice are gentle scale dissolvers. I tend to use the thick gel type on my sink which is stainless steel, it doesn't seem to damage the steel if you wipe it away quickly and try and get it only on the scale, not the sink. Please ignore all this if you have gold plated or other non standards taps or sink and get info from the manufacturer.