A: They can be removed with a technique called poulticing. You will need to use a strong solvent such as Methylene chloride to remove. You can find this chemical at most home centers. See our care guide for instructions on applying a poultice. You need to be very careful with these chemicals. You may opt to hire a pro to perform this type of work. You can find a pro at www.stoneandtilepros.com

Dr. Fred