If amber is a little muddy, wash it with soap and water and place in a bowl of ice water for a few minutes. Then just wipe with a soft cloth. This method of cleaning will help only for weak impurities, such as fat or soap deposits. After you washed the stone and has dried, you can drip some olive oil on a flannel cloth and RUB the amber.
Take your soft cloth and begin rubbing amber. For this fit an ordinary piece of velvet. A laborious process, sometimes the polishing takes several hours. But if you have the patience, a drop of resin will become transparent.
Can try to RUB the decoration of the GOI paste. A soft cloth and a small amount of paste Polish stone. But if it has areas with deep damage, amber can acquire a greenish color to get rid of that will be difficult.
If your stone is badly damaged, the only way out would be to visit the jewelry shop. Professionals will cause your jewelry in order. Sometimes to Polish amber using special equipment, without which the process of cleaning natural resin impossible.