Fein Teak Blades are used for caulking removal between deck boards. The blades are available in three widths: 3mm, 4mm & 5 mm. The end of the blade is "U" shaped, and it scoops out the old caulking, leaving enough room to re-apply new caulking. To prevent damage to your decking, select a blade that is slightly smaller that the caulk line you want to remove.
It's the fastest, easiest method to remove old caulk.