Hairline stress cracks on rear light cover cause/prevention/repair.
There has been no known collision/damage. There is a mark from a liquid that has run down the face of the light cover. Ive tried using a wet towel (water) to wipe mark away but it seems to be permanent. Image is post wiping. Is this liquid also responsible for the light cover stress cracks? What sort of liquid could cause this? How to repair - replace cover, glue, coat? Im concerned that it'll get worse and/-or leak moisture to the internal casing. Any ideas?