It happens that dennis@home formulated :

https://www.popularmechanics.com/car...er-works-best/

Thanks, but all those just report the immediate result. I am more
interested in how well it lasts, the UV protection.

I can get my lens back to gleaming with what I have at the moment, I
have done it before, but given a few months they are as bad again due
to lack of UV protection.