Have not been using water to clean it but the leather cloth that came with the diamond, "polishing" the diamond with that cloth all over on each facet.
I ll give a try with water and some dish soap maybe? What do you use to wash yours?
How could i further evaluate the stone for the transparency issues?
Unfortunately, as others have said, it’s hard to tell anything from the videos. Photos and videos of stones are notoriously hard to get right, so I would go by what your eyes see. You will not be able to capture it accurately in a photo or video. Additionally, whether on your hand, in your fingers, or on the cloth, the stone will not be seen at its best. You will be smudging it and blocking light. It will also be hard for you to move it around to different lighting conditions because you’ll be afraid of dropping it. I would suggest that you get one of those temporary stone holders to place the diamond in. Then you can put it on one of your fingers and move it around and get a much better sense of how it will look when it’s set. You will also be able to clean it with dish soap and warm water and then pick it up with the ring holder so you don’t get any smudges on it by touching it with your fingers. THEN move your hand around in different lighting environments.