What are the best treatments to improve the color grade of diamonds, and how to identify these treatments?

First of all, the ring bracket is more traditional. K-yellow or K-red ring holders can make diamonds with bad colors look one or two grades higher. The surface of the diamond is also coated with a light blue similar substance, which can show white. There is also a high-temperature and high-pressure treatment method, which removes diamond impurities and can artificially manufacture high-grade diamonds. There is also a laser that can permanently change the color of the diamond surface. The first method is easy to identify, just wipe it with alcohol, while the latter two methods are not easy to identify.