You just go to the yellow pages, look up a coin dealer, take the coins to his shop and take whatever he offers you and go home fat and happy. Well, that is exactly what a large number of people do. This is not the best way to maximize your earning potential, but it is very convenient. This shouldn't be really all that shocking since most retail outlets have this level of markup on most of the goods they sell. Many dealers will look at a pile of walking liberty half dollars, look at a few and state that they are worth silver melt value, despite the fact that a rare date and mint mark or variety may be lurking somewhere in the bag.
Collectors find rarer dates in junk coins with some frequency.
Most dealers just don't have the time or inclination to look at every coin that moves through their shop. Now, if you have a little knowledge, you can go through the bag sorting the common dates from the less common dates. You can also separate the higher grade coins from the rest before you go to the dealer. When you show the dealer the rare date coins separately, he is more likely to take a closer look because he doesn't have to take up so much of his own time to do so. Help him to help you as much as possible.