Platform shoes's sole (which seems to be the sole of beef tendon) is oxidized and yellowed because it has not been worn for a long time and has been left for too long.

Solution:

The yellowing of the bottom edge is mainly caused by the rubber oxidation of the sole. We can buy clothes softener or bleach from the market, take out a certain amount of products, dilute them with water and soak the soles in the solution. After a few minutes, the yellow spots on the soles will automatically fall off and become white and flawless. Because this solution is alkaline, don't soak the whole shoe in it, otherwise it will fade.