Prefinished pavers or plain concrete? Pictures? Help us help you.

Carol, as @millworkman stated more info would be helpful... In addition, your pavers are not that old, if you know or can get the name of the paver manufacturer from your contractor or from a place (if you purchased them) that would be even more helpful, because you can get cleaning instructions directly from the manufacturer.

I have paver driveway. It was not sealed and in the Fall it was discolored from wet leaves ( looked pretty bad. ) We had snow a few times and in the Spring the staining was not noticeable. So I am pretty sure there are ways to remove it.

Many thanks to all for the replies and I apologize for the delay. My pavers are made of concrete. For some reason I wasn't able to download pictures that were openable. I did not like the manufacturer's suggestion for 1 part chlorine bleach to 4 parts water b/c it sounded too harsh, and I was concerned about harming abutting grass. So instead, I used 2 cups powdered, non-chlorine OxiClean in 3 gallons of hot water and applied with a soft brush to wet pavers. It removed the stain 100%!