Buy new ones from dealer?
Shouldnt be expensive.. for sure cheaper than to sandblast and paint the old ones...
http://bmwfans.info/parts-catalog/E8...ack/#7184971_2
Moisture does corrode stuff in the boot... when you open it while raining it rains in and so on...
Years ago i had an issue where my third brake light on the boot lid had 3 of its right side LED-s constantly on... while driving and while parked all night.
Electrician found that bootlid harness plug connectors had corroded and voltage was somehow arking to the brakelight wiring, enough to light up 3 led-s but not the whole brake light. Cleaned the connectors and has been working perfectly since. Plug connection is under the boot floor in the rear side of the car... right where rain can get easily in when lid is opened.
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2009 35i DCT Havana brown with ivory white interior. Mods: Cobb stage 1+FMIC, Wagner EVO1 FMIC, BMS DCI, KW V3 suspension, M3 front control arms, Hardrace RTAB, Michelin Pilot Sport 4S tires.