Limestone is a soft sedimentary rock in which calcium carbonate is present. Limestone is derived from fossil deposits of marine animals and is often a buff or off-white color. It is possible to sand limestone, but only professionals should do so. If you have no experience in working with limestone you need to hire a professional to do this work, because there is a big chance that you will dull the stone.
Use water to cool down the limestone and lubricate the stone before starting the sanding process. Limestone is extremely sensitive to acid-based cleaners, so it is important to just use water. Using any other cleaner could damage the limestone.
Use sheet-mounted diamond pads and an orbital sander to sand the limestone. This is a very delicate process and because of the softness of limestone, it is important not to put too much pressure on the sander.
Clean the surface with water to get rid off the sanded limestone.
Do not use acid-based cleaners to clean limestone.