There are many products available for the protection, care and cleaning of natural stone. The following should be taken in account:

• Check that the chemical allows the material to breath
• Attention has to be paid to how often the treatment must be repeated
• When treated does the material change colour Some materials change
   their colour when they are treated
• Make sure the cleaner is none abrasive aggressive cleaners will  damages the
   polished finish
• The cleaning company should be attentive and knowledgeable to the needs of 
  natural stone