[Doug Huffman]

I feel your pain and wish you the best. Your concern about mineral spirits is good, but they are the best. Perhaps a brief judicious application as with a cotton swam and for just a moment then wipe it away.

Once you have recovered, learn about Aqua Pel Glass Treatment. I have used it on windshield glass for many years - since Rain-X was sold and the formula changed. For two years now I have used Aqua Pel fluoroalkylsilane on the whole body of the X5.

In addition to being hydrophobic, as is the effective ingredient in “ceramic” coatings, fluoroalkylsilane is also oleophobic and so effective against petroleum products. It is harder and shines better.

 

[Doug Huffman]

Seems like maybe the materials being used just don't hold up well.

It is technically challenging. Quite similar to ageing of tires due to UV exposure. The UV blockers are only skin deep in application and function. The abrasion is similarly just like tire wear. Tires abrade against the road surface and headlight covers are abraded by wind entrained road trash.