Just don't. A carburetor or just about anything is easier to service. You could take it all apart, rebuild that drive bearing assembly where your winder handle attaches, buy forward channel guide kits, replace all the rusty little clips on the latch/lock linkages, renewing as much as possible to avoid tomorrows typical problems. When this "like new" door goes back on the car, the wind noise and water leak fine tuning begins. If its a hardtop, getting the door glass to quarter glass mating and proper operation can take days.
There's a eccentric stop on the regulators that can be adjusted to let the glasses roll down lower. Easier to R&R the fuzzies. You could remove a few bolts to lift the vent window assembly straight up a few inches too. Work arounds to get painting done. Save the door gut surgery nightmare until the diagnosis says that surgery is req'd. Or... take it all apart now, build the door guts after the door is hung and aligned on the car. Either way plan to spend a lot of time and money doing a lot more than "cleaning". Good luck
