A little common sense will go a long way in getting those granite counter tops sealed properly! First, get a stone cleaner from the local stone wholesaler. Stone tech has a great product line. Read the instructions on the container. Always try any product in an inconspicuous area to ensure it doesn't damage the stone.
Once the stone is cleaned & thoroughly dried, the next step will be to apply the sealer. As before, trot on back down to the local slab wholesaler, & get a good quality sealer. Stone tech impregnator pro is what we use on all of our installations. Again, it doesn't hurt a thing to read the manufacturer's instructions on the container, & try a small spot somewhere in a corner.
Get the surface wet with the sealer & let it soak in until it doesn't soak in any more. As a general rule you do not want to let the sealer actually dry on the surface. Read the can & see what it recommends! Most if not all sealers will leave a residue on the stone if you actually let them dry on the surface. Some of them leave a film that is very difficult to remove if it is left to dry, in fact some of the old ones we used were a real problem in this regard. The impregnator pro has given us no problems in this department however. In the event that it dries on the surface, it is relatively easy to buff the surface clean with a clean white cloth. If you like, you can re-emulsify the dried sealer by getting the surface wet again with another rag wetted with sealer, and then dry it down before it films over.
A second coat after an hour or four is not a bad idea. This will more fully seal the stone, as well as catch any areas you may have missed on the first go around. Basically you are saturating the surface till it won't take any more, then buffing it to its previous shine.
Regular daily cleaning can be done with a damp cloth followed with a quick dry one. Like washing a car, (especially black!) if you let hard water dry on a shiny granite surface, it will leave spots & rings. These are best avoided by simply drying the surface with a clean (read ?non salmonella?) cloth immediately after the damp one. Weekly you can do a clean with a stone cleaner product like Stone tech's Revitalizer.
The sealer should be re-done once a year (forgive me if the can says otherwise), & if coupled with the other cleaning mentioned, your countertops will remain looking new for a lot longer than you will!
