DIY: HOW TO PUT THAT SPARKLE BACK IN YOUR DIAMOND (RING)
all it takes is 10 secs

take an old toothbrush, add some toothpaste and gently brush the little stone.. pay attention to the bottom of the diamond (that's where dust/lotion etc usually gather, thus obstructing light from shining through).. then rinse off.

TADA! brand new as a baby!