I agree with the vacuum. It will pick up all the dust and dirt than using a liquid to clean it. If my mom could get everything out she would scrub it with a toothbrush to loosen that dirt, them vacuum again.
Put a coat of car wax on the track and the dirt should not stick. If it does, just wipe with water and dish liquid. The doors will also slide easier.
WD 40 👍🏻👍🏻
I used WD spray degreaser first. Just spray it in the tracks and let it sit a few min then wipe out the tracks very well. Then I used the silicone spray in the tracks so the door would slide easily. I think the previous suggestion of car wax might be better after you cleaned the track, because it would not attract dirt.
I use a vacuum, then try to clean with just a wet paper towel and toothbrush. I love these other ideas!