White siding turning orange

[Infinity]

Maybe this:

@Infinity

Sometimes yellowed vinyl is due to a reaction in the UV layer (or absent UV protection) in the plastic. I’ve heard that certain acids are effective in reversing this type of yellowing. But I wouldn’t make any promises.

Try EacoChem’s OneRestore. WCR sells it:

https://shopwindowcleaningresource.com/eacochem-onerestore.html