[JohnPercy]

Hello

I'm trying to remove yellow stain on my white shoe sole, i tried with hydrogen peroxide 3% but it doesn't work maybe because its too weak, should i try with 50%? or i need to dilute it to lower percentage. because I'm afraid it will ruin my shoe, it was a gift from my mentor so it's a valuable shoes for me, or maybe do you guys have other alternatives to unyellow white shoes

[Corribus]

First stop: How old is the peroxide, and how long was the contact time? If the substance causing the stain has permeated into the material, peroxide (even if fresh; it has limited shelf life) may be ineffective because it cannot get to what is causing the stain. You may need to soak for a while.

Have you tried bleach? High concentration of peroxides may damage the underlying material.

Do you know the origin of the yellow stain?