I am remodeling a beach house in northern Indiana and am seeking to refinish a concrete floor that was covered with carpet squares. The adhesive/mastic is a thin tarry material. I tried to remove it with paint thinner with modest success. I rented a floor grinder with the hope of taking off the remaining adhesive and grinding the concrete to prepare it for an epoxy finish. Unfortunately, all the grinder did was spray the adhesive around the room. (See attached picture.) What is the best option for removing the adhesive?
