No pain no gain

TÜV have conditionally treated my "stressed" lenses.
Condition: a few "strikes", and strongly yellowed, clouded lenses with greatly reduced brightness (I realize only now after the treatment).
Duration: Fairly lengthy process (about 6 hours at a Mercedes 4-eye (W210, Bj.2001))
Result: Not only that it looks visually back a lot better with bright windows, the reflectors are visible again, the luminosity is restored. The effort has paid off for me. And no pain no gain :)
Alternative would have been "new" lenses in the "bay" to the 90 euros each.
Future: Whether it holds and does not start up again? According to the description can you repeat it from time to time. Rhythm?
The fifth star has been lost for quite small sandpaper strips. This could have been greater or more. When two lights like it might be enough.
My recommendation you have anyway.