Caulk is applied soft and then hardens, forming a protective seal. Because of the way it is applied, it is easy to accidentally drip caulk on other surfaces when caulking. Caulking drips are easiest to remove when fresh (you can usually wipe it off with a damp sponge); however, if caulk has dried on vinyl, you can remove it with the right chemicals and tools, which are available at hardware and home improvement stores.
Use the putty knife to try to pry loose any of the caulk. If you can, remove as much as possible before continuing to the next steps. Because vinyl can be easily damaged, use gentle strokes with the putty knife to avoid gouging the vinyl.
Apply caulk remover directly to the caulk, covering it completely. Remember to wear protective gloves so you don't get this on your hands.
Let the chemical penetrate the caulk. This process usually takes several hours, but you can check it every half an hour.
Slide a putty knife beneath the caulk to see if it has softened. If so, work the putty knife further beneath the caulk, lifting it off the vinyl siding.
Apply more caulk remover on any remaining caulk, if there is still a lot left. Otherwise, scrape the caulk off with the putty knife.
Dip a sponge or cloth towel in warm water. Rinse any leftover caulk and caulk remover from the vinyl.