Thin scratches are covered with a layer of varnish. If the scratch is deeper, sand the metal with a mild abrasive, until the scratch disappears. Metal polishing paste has low abrasive properties, if the scratch was still visible after polishing, prepare a paste of painter's chalk spread with denatured alcohol, paraffin or white spirit. Wrap a rag around your finger, dip it in the paste and grind the damaged surface with circular movements. Rinse the surface and repeat the operation from scratch. Scratched brass and copper can be sanded with increasingly finer grit sandpaper, lubricating the surface with oil. Never use abrasive abrasives to grind soft metals, such as tin or silver. remember, that even the slightest rubbing can destroy the patina on bronze products.
In most cases, minor scratches can be hidden under a layer of varnish. To remove scratches on the silver surface, use denatured alcohol mixed with polishing rose (available at jewelry stores).