Best done after sweeping or vacuum. The job conditions will dictate frequency. The most frequent problems encountered with stone floors are related to the floor simply not getting effectively washed often enough. Dirty mop water residue is common and a cause for much complaint. A two bucket rinse method is highly effective in keeping floors from graying out due to soil residues.
Natural soaps are low-tech, inexpensive and user friendly.
Vegetable based soaps are best. Specialty soaps formulated for use on stone are highly recommended and desirable on most natural stone floors and other stone surfaces. The detergent used for stone cleaning should be carefully evaluated for compatibility with the stone. Detergents are typically used with water and may determine the pH of the cleaning solution. These are used for removing grout haze, removing mineral dposits and for rust removal.