How do I clean sliding glass tracks?

Vacuum out and use a toothbrush.

q tips. get the jumbo box. you can use a couple at a time.

A old toothbrush or a baby bottle brush is a good cleaner or you can buy tinier little brushes--like very small bottle brush--and those work well too. Sometimes a wet Q tip is helpful or a small stiff paint brush!

Try vacuuming the trash first then use a toothbrush and clean it with a peroxide and baking soda paste

I use a steam cleaner to clean my tracks (and everything else for that matter) HomeRight makes a good product and it is available on Amazon.