Before discussing color and clarity grading here are some pointers on cleaning a loose diamond effectively. When cleaning a loose diamond it could be as simple as wiping it with your lint-free gem cloth. Sometimes though, especially when coming out of a secondhand mounting, it will take much more than a wipe. For heavy grime, take about a half teaspoon of table salt in the palm of your hand and rub the diamond with force in the salt. (Be careful not to cut or puncture yourself in the process). Try to rub the diamond between your thumb and forefinger with the salt. This is extremely effective in getting the majority of refuse off of the diamond’s surface. After the salt treatment rub the diamond with your gem cloth between your thumb and forefinger.
Further into the course we will discuss acid boiling, which is the most thorough method, but for now the salt and gem cloth will suffice.