you can... if needed, remove the lens completely off the housing. if i remember correctly there are 3-4 "tabs" that need to be pryed-off carefully... once off you'll be able to access the innards... and clean up the inside of the lens... which is close to impossible to do.
much easier cleaning euros...
btw... this operation needs the whole housing removed from the car...
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85 190E 2.3(SOLD)
86 230E (-->300D) sold
87 300D (-->300TD) sold
68 250S w/ a 615 and manual tranny (RIP)
87 300TD (SOLD)
95 S280 "The KRAKEN" (Turbo 2.9 602 transplant) traded
86 190E 2.3... current project