My recipe consists of cheap ingredients. I start with one aloe-vera leaf, which I squeez the gel out of and mix with an ounce of concentrated lemon juice. 3 ounces of rubbing alcohol and three ounces of distilled water, then give it a good shake.
You only need to pour a small amount into a tiny cup and set your jewelry in it. I let it soak for about 20 minutes while I did other stuff. A soft child's toothbrush can be used to gently scrub areas such as prongs. Rinse with plain water and dry with a soft cloth or paper towel.
This isn't something to use on a porous gem like a pearl or opal. But for hard or sparkling stones, it works great. It's also more gentle than ammonia. Best of all, it takes pennies to make and it doesn't hurt that I almost always have the ingredients on hand.
Make a small batch of this up and keep it under your kitchen sink. Take your rings off at night when you do the dishes, or set them in this before you go to bed and let them soak over night. Your stones will look great and have a lot more sparkle because they'll be clean. And what good is bling if it doesn't sparkle???!!!