If you use toothpaste, make sure it is not grainy as this can scratch the watch crystal.

Mineral crystal is more scratch-resistant than acrylic crystal, and tends to crack or shatter under extreme temperature or when hit from an angle.

Sapphire crystals are harder than mineral glass or acrylic crystal and are more likely to withstand cracks and breakage than other types of watch glass.

Do not use any type of polish on a watch crystal you are unsure about, as this can cause damage.

Using painter’s tape will protect the rest of your watch from being damaged during the polishing process. While you don’t need to cover the band or strap, you might want to remove it to make the polishing process easier.

Keep the pressure light as you buff in a circular motion for 2-3 minutes.

Try taking your watch to a local watch repair shop and ask them to replace the watch crystal. Consider returning the watch to the manufacturer and ask them to replace the watch glass.