I'd take it to a self service wash or use a pressure washer, and spray the bottom of the window sill pretty good (windows closed obviously) to dislodge any grit that is stuck between the window trim and window. do this on all.

After that, take a small rag and some glass cleaner, roll down the window halfway, and wipe out the "channel" at the top of the door that the window sits in when closed, lot of grit tends to sit in there.

Hope that helps.

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2018 Ram 2500 6.7L Cummins 68RFE
19k miles -Bright White/Black - Big Horn Sport - Crew Cab Short Bed
2013 X5 35D (CEO's) - Born on 5/17/2013 -
82k miles - Alpine White/Cinnamon Brown/Premium Pkg, Sport Activity/Premium Pkg and Sound/20" Style 214/Running Boards