Composition Of Coins Prior To 1908

I'll just give you the full list of metal compositions, since some denominations have a lot of metal changes.

Pennies:
1858-1859: 95% Cu, 4% Sn, 1% Zn
1876-1941: 95.5% Cu, 3% Sn, 1.5% Zn
1942-1977: 98% Cu, 0.5% Sn, 1.5% Zn
1978-1996: 98% Cu, 1.75% Zn, 0.25% other
1997-2012: Copper-plated zinc
2002-2012: 94% steel, 4.5% Cu, 1.5% Ni (Copper-plated steel)

5 cent silver:
1858-1919: 92.5% Ag, 7.5% Cu (Sterling silver)
1920-1921: 80% Ag, 20% Cu (.800 fine)

5 cent nickel:
1922-1942: 100% Ni (pure nickel)
1942-1943: 88% Cu, 12% Zn (tombac)
1944-1945: Steel coated with .0127 mm layer of nickel and .0003mm plating of chromium (chrome plated steel)
1946-1951: 100% Ni (pure nickel)
1951-1954: Steel coated with a .0127 mm layer of nickel and chromium plated
1955-1981: 100% Ni (pure nickel)
1982-2001: 75% Cu, 25% Ni (Cupro-nickel)
1999-present: Nickel plated steel

10 cent:
1858-1919: 92.5% Ag, 7.5% Cu (Sterling silver)
1920-1967: 80% Ag, 20% Cu (.800 fine)
1967-1968: 50% Ag, 50% Cu (.500 fine)
1968-2000: 100% Ni (pure nickel)
2000-present: Nickel plated steel

20 cent:
1858: 92.5% Ag, 7.5% Cu (Sterling silver)

25 cent:
1870-1919: 92.5% Ag, 7.5% Cu (Sterling silver)
1920-1967: 80% Ag, 20% Cu (.800 fine)
1967-1968: 50% Ag, 50% Cu (.500 fine)
1968-2000: 100% Ni (pure nickel)
2000-present: Nickel plated steel

50 cent:
1870-1919: 92.5% Ag, 7.5% Cu (Sterling silver)
1920-1967: 80% Ag, 20% Cu (.800 fine)
1968-2002: 100% Ni (pure nickel)
2000-present: Nickel plated steel

1 dollar voyageur:
1935-1967: 80% Ag, 20% Cu (.800 fine)
1968-1986: 100% Ni (pure nickel)

1 dollar loon:
1987-2012: Aureate bronze plated on pure nickel
2012-present: Multi-ply brass plated steel

2 dollar:
1996-2012: Ring: 100% Ni (pure nickel); Core: 92% Cu, 6% Al, 2% Ni
2012-present: Ring: Multi-ply nickel plated steel; Core: Multi-ply brass plated aluminum bronze

5 dollar:
1912-1914: 90% Au, 10% Cu

10 dollar:
1912-1914: 90% Au, 10% Cu

About the plated coins:
Red coins are made using a two-layer process. The first layer is nickel and the second is copper.
White and yellow coins are made with a three-layer process. for white coins, nickel is layered first, followed by copper and then another layer of nickel.
For yellow coins, the final layer is either brass or bronze.

That's a handy concise summary! Nicely done, SlurExe97!