How do you restore shine to a Gemstone or diamond?

What is the best home remedy for restoring shine to a gemstone or a diamond or cubic zirconium.|||Cubic zirconia is man made and often looses its luster over time and cannot be restored. You can have genuine stones professioanlly cleaned at little or no charge. I would recommend this particularly with gemstones as some are delicate or porous and you can permanately alter their color/clarity with heat and chemicals.|||Soak the diamond in gin!|||My mom always kept an old toothbrush and would polish her jewelry with toothpaste. They were always shiny and sparkly!