For Natural Stone:
Use antibacterial dishwasher detergent and warm water. If streaks are bothersome, use a daily stone cleaner.
For Quartz Surfaces:
Periodic resealing is suggested if a 15-year sealing is not purchased. To test to see if the tops need additional sealing, pour a puddle of water on it and let sit for five minutes, then wipe off. If it leaves a dark spot on the stone, it should be resealed with a penetrating sealer (available at any big-box home supply store).
Things to Avoid
Do not use cleaners that contain bleach, acids, ammonias, detergents, abrasives and oils (i.e. oven cleaners, Comet, Soft Scrub, SOS, products with pumice, batteries, paint removers, furniture strippers, silver tarnish removers, etc.).
A stain is a discoloration of the stone; however, the surface finish of the stone remains smooth. Avoid stain-causing items from sitting on the stone for prolonged periods of time. If properly sealed, natural stone is highly stain resistant, but not stain proof. Prompt cleaning of spills is always a good practice.
Harm or Distress
Do not let blunt or heavy objects hit the surface—especially the edges—it can chip the stone. Heavy weight on counters is not recommended, so do not stand on countertops. Sliding abrasive objects (i.e. clay bowls, carbide-tipped tools, a sandy sole of a shoe, etc.) can also harm the surface.
Etch marks are a chemical burn that forms when acid, ammonia, or alcohol comes into contact with the calcium carbonate element that exists in certain natural stones (marble, travertine, limestone and dolomite). These marks look like the finish or the shine has been removed from the surface of the stone, and typically feel a little rough to the touch. Avoid acidic foods from sitting on the stone for prolonged periods of time. Again, get into the habit of cleaning up spills immediately.
High heat from items like toaster ovens, crock pots and coffee makers can cause seam adhesives to fail and thin strips to crack. Stone is heat resistant, but keep intense heat away from the seams and thin strips of your countertop to avoid these issues.