On this type car removing & cleaning isn't really an option, due to design.
Replacement is the answer. To access the sensor you must remove the carpet in the trunk & have a very large socket or wrench(36mm). Also the fuel level must be below 2/3 full or you will have a mess.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)