Slate is a porous
stone material, so should be sealed. Get a special stone floor sealer from
the flooring dealer or building supply. The sealer penetrates the upper
surface of the slate, and protects it from soil and scratches, and from
grease.
Slate floors can be
washed with a detergent and water solution, and rinsed well. They are not
damaged by alkali cleaners, but strong solutions are not needed for
cleaning. A water-based, self-polishing wax can be applied over a clean,
dry, sealed floor for extra protection and shine. Weekly damp mopping with
a barely damp mop on a waxed floor will keep it clean for quite a while
before the washing with detergent is needed.
If one has an
electric polisher, solvent-base polishing wax may be used to clean and
wax. This must be buffed.