I know people coin roll hunt. But you should also consider "Mint Set Hunting" (MSH) at shows. Below are three errors I have that were found in Mint sets. Not big type error types, but it makes you wonder what could be hiding in plain sight. Error coins in Mint sets have the potential to sell at higher premiums than as stand alone pieces simply because of the probability they would make it to a Mint set vs. being discovered in circulation or in rolls/bags. In order is (1) a grease strike-through cent, (2) a very strong dime die clash, and (3) a silver quarter doubled die. 1970-S 1c Obverse/Reverse Strike-through Grease 1965 10c Strong Die Clash Silver 1963 25c DDO (thanks, @Fred Weinberg )
