Mastic sealant is often used in areas where there is a need for flexibility and a moisture-resistant seal. Mastic sealant is flexible, pliant and waterproof. It is also very easy to install. This makes it the ideal seal for areas such as bathtubs, showers, sinks and bathroom floors. Getting mastic sealant up again is a bit of a task, but using easy-to-find items should make the job simple, and will save you money because you are doing it yourself.
Wash the area thoroughly with an all-purpose cleaner and a scrub brush, so there is as little dirt as possible on the mastic sealant. Allow it to dry, and leave the area unused for 48 hours.
Burrow the tip of a utility knife or scraper underneath an edge of the sealant. Begin to peel away the sealant. Hold the blade flat under the surface of the sealant, and inch your way around.
Prepare a garbage bag with a seal or good closure. As you get the mastic off the surface, place it into the garbage bag. When you are through, seal the bag well before disposing of it.
Pour some white spirit onto a microfiber cloth, and use the cloth to rub any marks or stubborn bits of mastic that remain on the surface.
With a dry microfiber cloth, thoroughly dry the surface where the old mastic was removed, and any area touching it. Dry this area again before putting on a new sealant.
Keep areas with mastic sealant dry and clean for longer-lasting seal.
Use chemicals in a well-ventilated area.