DON'T CLEAN COINS! As a rookie, use that as a general strict rule. With more experience there are some gentle methods which can be used, but for now, don't...
1967 pennies - very common indeed. However a few choice (absolutely fully bright lustred) examples could be kept. A reputable dealer will sell them for 50p or £1. There are a few misstruck pennies, if you see any of those put it aside. For example I have one that is obviously genuine but doesn't ring when you drop it, it just clacks.