Here are some methods to clean your diamonds

1. Make a warm soapy solution using any mild household liquid detergent (make sure it doesn’t contain chlorine or ammonia) in a bowl. Brush the jewelry with a soft clean brush until lather is formed around it. Take special care to brush the back of the diamond as this will be the area that has collected the most oil and dirt. Wash in warm water (do not clean your jewelry over the drain!) and dry with a soft, lint-free cloth.
2. Take 4 parts of cold-water and 1 part of very mild dishwashing detergent. Soak the jewelry for several minutes. Clean the diamond gently around all sides of the mounting with a soft brush. Rinse the pieces in the solution once more and drain on a tissue paper.
3. Buy one of the branded liquid jewelry cleaners, choosing the one that is suitable for your jewelry. Read the label carefully and follow the instructions.
The Ultrasonic Cleaner: There are many types of these small machines available to the public today. They are used to remove hardened dirt on diamonds which does not go away by conventional cleaning. By sending high frequency sound waves through a detergent solution in a metal cup, ultrasonic cleaners make vibrating fluid to remove accumulated dirt and grime in minutes. However, they can also shake loose stones from their mounting, so this method shouldn’t be used on fragile settings like estate jewelry (jewelry that is of vintage and/or antique nature) and is best undertaken by a professional jeweller. Always follow the manufacturer’s instructions and warnings before using these machines.
Do not touch your clean diamonds with your fingers, as the oils from your hands will leave a film on the stone.
Don’t use harmful solutions. Chlorine (as in household bleach) or abrasives (such as household cleansers or toothpaste) should never be used when cleaning diamonds, especially those set in jewelry. These erode some of the metals often used in diamond settings, and may loosen prongs, or even dissolve the metal completely.
Antique or delicate jewelry should nearly always be cleaned by a professional jeweler. Certain metals will naturally change color over time and so your antique jewelry may not be as dirty as it looks. Professional jewelry cleaning is often complementary and if not is very inexpensive. A professional jeweler will also inspect and repair any loose settings which may cause problems down the track.
Regular cleaning will keep your diamond jewelry in gleaming condition and ready to sparkle for that special occasion.