How To Clean Yellow Clear Phone Case. A simple and practical solution to clean clear phone covers. Sunlight will yellow TPU over time.

You could try making a paste out of baking soda vinegar using about a 12 cup of baking soda to a tablespoon or so of vinegar. This is likely how they are stored before sale. Sunlight will yellow TPU over time.
For how to clean a yellowed clear phone case.
Add 1-2 drops of dish washing liquid to 1 cup 240 ml of warm water. If scratches are still visible apply some denatured alcohol to the microfiber cloth and rub the phone again. This discoloration is caused by exposure to rust and the formation of mold. After years of exposure to water and humidity clear silicone can begin to yellow and blacken.

