[Grumpy old man]

You already have the cab back on the frame and glass installed so sand blasting could turn bad fast besides being a huge mess , Use a angled pick and small blade screw driver to pick all the heavy sealer out and then a wire wheel to clean the rest out , get it as clean as possible then prep and shoot the drip rail with epoxy primer before using self leveling flow grade 3M seam sealer .The cab has to be level at the seam for it to flow correctly , Always easier if the cab is off the frame . I used an air powered windshield tool to clean mine out and it took a bout 45 minutes , Be careful if you do the same it can eat right thru the sheet metal if your not careful .