Your 1919 Lincoln cent is a very nice find, but not overly rare. The Gov't made over 350 million of them at the Philadelphia Mint that year. My latest prices catalog lists the 1919 cent at about a $1.00/ 1.50 (US) in average condition.

As far as cleaning goes....don't. Perhaps a little water if there's something sticky on it. Pat it dry and let it come to room temp before putting it in a holder. It will get shiny if you clean it, BUT you cannot restore the wear from being passed from hand to hand. Besides, most collectors would not want it if it has been cleaned. Many collector coins have been ruined that way.

Enjoy your find. Almost everyone, including me, started out collecting Cents. After over forty years, I'm still at it.