I think this would be a good sticky topic. A lot of diesel benzes I see suffer from "sooty tail light syndrome", in some cases so severe, the left tail light lens is jet black (doesn't look so good when you park your 300SD next to a 560SEL). I for one would like to get my tail light lenses clean again.
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.