Caulk usually dries to an elastic or spongy consistency. Very old caulk is often dry and brittle and is much easier to remove than caulk that is freshly dried. Caulking is applied on a variety of surfaces, such as tubs, showers, windows and around pipes and electrical lines for air sealing. When caulk has dried to the point that shrinkage or cracking has occurred, remove the old dried caulk before adding new caulk to ensure a water-tight or air-tight seal.
Pull as much of the dried caulk out of the area as you can by pressing a spackle knife into the caulk and pulling the caulk out of the crevice.
Cut along the top and bottom edge, as close to the surface as possible, with a razor blade.
Lift one side of the caulk and pull it out of the corner. If it is hard to remove, use a pair of pliers to get a firm grip on the caulk and pull with even force.
Insert a spackle knife at the bottom and top of the caulk to break it away from areas inside the crack or gap, and pull any remaining caulk out of the area.
Scrape the last traces of caulk off the surface with a razor blade. Hold the razor very flat to remove the caulk and avoid scratching plastic.
Remove caulk without solvents if possible to avoid damaging surfaces. However, to completely remove caulk, purchase a solvent developed for removing caulk from a home improvement center. Apply a bit of the solvent to the remaining caulk in an inconspicuous area to test that it will not damage the surface; allow time for the solvent to soften the caulk and wipe off with a rag or scrape off with a spackle knife. If no damage occurs, continue to remove the remaining caulk with the solvent. Do not use a solvent to remove dried caulk around electrical, cable or plastic plumbing; it will soften or melt the plastic coating.