How can I prevent cloudy headlamps?

A couple of years ago I had an MoT failure on my 2003 MG ZT due to cloudy headlamps, requiring them to be polished. They have subsequently began to similarly deteriorate again and I'm dubious that this a long term solution and suspect there is a limit to how many times it is possible to effect a remedy via this method.
Having recently bought a new car (Citroen eC4X), which I intend to keep long-term - and also mindful of the high cost of replacement of modern LED headlamp units - I would like to try to prevent any similar issues arising in future. Aside from regular cleaning and avoiding parking in direct sunlight, I would like to know if you have any other suggestions or recommendations for a product that will help protect the plastic lenses and in particular prevent them becoming discoloured and opaque.

Asked on 24 July 2025 by Stephen Horseman

Answered by David Ross
Alongside regular cleaning, applying a good quality sealant that provides protection from UV rays is the best approach to reduce the likelihood of clouding and discoluration. Sonax Profiline Headlight Coating is a good option that comes in individual sachets and offers up to one year of protection.
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