Why is stone maintenance necessary? Stone is mistakenly assumed to be “stain-proof”. However, all stone is porous and delicate to some degree. If natural stone is not properly treated with a high-quality protective sealer, water, oils or other liquids can easily penetrate the surface, leaving stains that could become permanent. In addition, if the wrong maintenance products are used, they can cause major damage as well. With the use of advanced stone restoration methods, Kelly Cleaning in Ventura uses protective sealers, impregnators and enhancers that penetrate all types of stone, tile and grout, protecting your surfaces from staining.