Sounds like rocks scratch my rear sliding window

Has anyone else experienced this? I just got my first tundra and when I go to roll the window down or up it seems as if little pebbles are struck between the rubber piece and the glass.

Any one have any recommendations?
I already tried to look to see if anything was scratching and no luck finding anything

 

Probably just dirt build up inside the window track or in between the rubber seal like you said. Happens all the time down here in the desert. I usually take a healthy dose of the foaming spray window cleaner while lifting the rubber seal away from the window, let it soak a bit, then wipe away with a microfiber or strong paper towel. You could just spray some water or used compressed air too. That's my recommendation

 

Any particular brand?

 

Sprayway is what I use, it's available pretty much everywhere (Walmart, Sam's, target, etc)