1. If you want to clean it, you can wipe it with salt first, then wash it with water, and finally dry it with a clean cloth. In addition, you can also wipe the glass with a towel dipped in beer or warm vinegar, and you can also quickly eliminate the dirt on the glass.

The reason why there is watermark on the glass is because the water stain on the glass is not clean. In order to avoid this phenomenon, we can first sprinkle a small amount of alkaline surface on the glass with edible alkali, then soak it for a few minutes, and then wipe the glass with a sponge to make it as bright as new.