Sienablue11 says:

Hand lotions, hair styling products and everyday grime can leave a film on your diamond that keeps it from sparkling. Those materials can even accumulate into a thick layer of gunk on the back of the stone if you wait too long between cleanings.
Diamonds are the hardest substance known, but coatings and other materials used to enhance them can sometimes be removed by harsh cleansers and vigorous scrubbing, making it even more important to clean the gems with care.

Do you know if treatments were applied to your diamond before it was placed in a ring setting? If you do, that’s great, because it means you’ve probably done enough research to know how to keep the ring clean without damaging it.

Gentle & Effective Cleaning for All Diamonds

Soak your diamond ring in a warm solution of mild liquid detergent and water. Ivory dishwashing liquid is a good choice, but any other mild detergent is fine.

Use a soft brush if necessary to remove dirt. Soft is the word—don’t use a brush with bristles that are stiff enough to scratch the ring’s metal setting.

Swish the ring around in the solution, then rinse it thoroughly in warm water. Close the drain or put the ring in a strainer to keep from losing it!

Dry the ring with a lint-free cloth.
If the ring needs extra help, a Water Pik provides a stream of water to flush away small bits of grime. You can also use a wooden toothpick to carefully push dirt away from the stone and setting.

Cleaning Unfilled Diamonds

Diamonds that have not been fracture filled can be cleaned with a solution of ammonia and water.

Use the gentler liquid detergent solution for fracture filled diamonds, because ammonia can eventually cloud or remove the coating that’s been placed on the stone.

If Your Ring Contains Other Gemstones
The method you use to clean any piece of jewelry must protect its weakest element. If your setting includes other gems, use a cleaning method that is suitable for the less durable stones.

Household Chemicals
You might already protect your hands from harsh chemicals, but if you don’t, think about your fine jewelry. Remove your rings or wear gloves to protect them from products that contain chlorine, because it can damage metals. Avoid dripping bleaches and hair dyes on your fine jewelry.

princess kimberley says:

if u soak ur ring in a water and cloudy amonia mix for a few minites and then dry it with a dry soft cloth it usually gets out all the hidden grime and makes it shine.