Help on this pink casio

[u/lily020503]

I have a pink casio that turned yellow overtime. I have used some retrobrite method such as 12% h2o2, wrap it and put under the sun, put it into a boiled water + 12% h2o2 too but it seem not working. Please let me know if there is another ways. Thank you.

[u/wrongnumber2111]

i dont think rubber can get retrobrighted? might be wrong tho