Pennies (BRITISH) = 1993 and before are bronze, 1967 and earlier are half dollar sized, not nickel sized. 1902 low sea level, 1918 KN, 1919 KN, 1926, 1933 (7 known) and 1954 (1 known) are all semi-key or key dates, Victorian and earlier is good to keep also. Generic Lad (a member here) may assist you further on pennies.
Cents (USA)= 1982 and before are bronze, some 1982 are bronze as well (you can do the sound test to separate or weigh them [zinc = 2.5 g, bronze= 3.14 g], 1909-S VDB, 1909-S,1910-S, 1911-S, 1912-S, 1914-D, 1914-S, 1915-S, 1922 weak D, 1922 no D, 1924-D, 1931-S, 1955 double die are all key or semi-key dates. You should also keep Indian Head and before cents.
So just remember, pennies are British, cents are American