In industry it is observed that equipments like height gauge, V block, slip gauge, angle plate and other tools sometimes stick on granite surface plate. This is due to deposit of dust, grease, finger prints and other foreign particles on the working surface. The dirty surface makes the measurement wrong.
Just spray on the working surface wait for 20 to 30 seconds scrub with cotton cloth.
Clean with dry cloth. After it gets dry rub the surface with the dry cloth.
Now observe how smooth the working surface is. This cleaning not only makes the working smooth but also reduces the wear and tear of the instruments to be used on these surfaces. This cleaned surface gives correct measurements.