I want to fix a failed part of caulk in my tub that has mildew. I hear that all of the old caulk needs to be removed because new silicone will not stick to old silicone. Can I remove just the section that is bad? The bad section is connected to the caulk that is still good and it would take a lot of work to remove all of the old caulk. If I only remove the bad caulk section, what do I do with the border between the new caulk and the old caulk that is still good?
-Edwin