Method to clean sliding door.

what is the correct method to clean the sliding door mechanism and roller. Any special cleaner needed? after cleaning need to lubricate it back?

Well, you can use WD40, Silicon luquid, some liquid soap, and some grease.
1.First you need to clean the roller tracks, there are 3 of them, on the roof, under the rear window and under the footstep.
clean using silicon and wipe the track using cloth.
Spray the roller with WD40
hear the roller sound while you slide it back and forth, if there still a rough sound, means there's still dirt.
Especially the part when the rack bent inward to the body. Very hard place to reach and often forgotten.

2.Clean the mechanism and join of the door with liquid soap, and toothbrush.
After that spray some WD40 on it, add grease if you like.