Officially, a trained technician should perform maintenance on Dolev.
Other than that, you can clean optics with lint-free cotton swab and very clean alcohol from time to time, grease the spindle (selected greases or very pure silicone oil only due to low tolerances of spindle mechanism) and carriage (that big metal thing that is under spindle and carries whole spinner assembly). Take all cassettes out, pull the cassettes assembly and wipe dust from all that you can reach with very clean alcohol. Sometimes blow the dust out of CPU unit and cards. Clean all the vacuum holes on drum with needle. Clean all the sensors like the carriage home position with lint-free cotton swab and very clean alcohol from time to time, check/level the tension of the film on tensioners (if you have problem with not loading the film from time to time, tensioners can be your problem), check the conveyor belts (if the film does not come out machine but comes out of drum, conveyor belts can be too lose), etc.
Sometimes it is cheaper to call in the tech to do his magic (like twice a year) and make him responsible for the perfect cleaning and reliability of the machine.
