Thank you for the enquiry!
Crazing is a network of lines or cracks in the glazed surface. It happens when a glaze is under tension, possibly from being washed with hot water, or perhaps a bleaching product.
All Renovo products are water-based, and therefore impossible to penetrate the plastic surface and cure the results shown in the image. Therefore, we can only surmise that the window has previously been exposed to hot water or a bleaching product that has caused the crazing.
Unfortunately, this is not a reversible process, and we can only suggest you may need to replace the plastic window.
I hope you found this information helpful, and please do not hesitate to contact me if you have any further questions.
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