It just requires familiarity with the coins. Someone with no experience with them will have issues, but someone that has used them regularly for all his life should know.
I know in Canada many coins also have different edging, particularly useful for for the dime (rough) and penny (smooth) that are roughly the same size.
I know in Canada many coins also have different edging, particularly useful for for the dime (rough) and penny (smooth) that are roughly the same size.