Drip rail sealant?

I use this seam sealer but have used many brands in the past. Dynatron 552 Brushable Gray Seam Sealer This and 3M caulking tube product are my go to products though.

I use an old 1/4" wood chisel with the corners softened to pop the old stuff out. After somewhere near 40 years it is usually hard enough to pop out in chunks. If not a heat gun will help.