1971-1974 Full US Mint Silver Proof "Blue Ikes" and "Brown Ikes" Run, In Original Packaging - 8 Coins Total. "Blue Ikes" are uncirculated, 40% silver Eisenhower dollars packaged in blue envelopes by the US Mint. "Brown Ikes" are 40% silver Proof Eisenhower dollars issued from 1971-1974. They take their name from the fact that they were issued by the US Mint in brown colored faux-wood boxes.