After time, semi-precious and precious gemstones lose their luster, just as with gold and silver. This is because of the dirt and residue that builds up on the stones. The stones can easily regain their polish with a simple cleaning. There is no need to purchase expensive cleaners or polishes, because they contain the same ingredients as the solutions that you already have under your kitchen cabinet. The main ingredient, ammonia, can be found in products such as 409 and Fantastic. Add the ammonia-based cleaner to a sink of warm water. Place the semi-precious stone or jewelry in the solution and leave overnight. According to Asia-gems.com, it is important to not put a heat-sensitive gem in a hot solution, as it might fracture. (See Reference.) Use a toothbrush to clean off dirt and residue. Rinse with warm water, and pat dry with a cloth. Use the Sunshine polishing cloth to brighten and shine the semi-precious stone and jewelry.