1968 United States Mint Set in Original Government Packaging, 10 Coins Inside!. Original packaging: The new Mint Sets retained the old Pliofilm packaging, but with a twist. To differentiate official Mint Sets from privately made sets, the Mint added color to the edge of the plastic: blue for the Philadelphia and San Francisco coins, and red for the Denver coins (the addition of colored edging was actually proposed in 1964). The five coins from the Denver Mint were placed in one pliofilm package, while the Philadelphia and San Francisco were combined in another. The two pliofilm packs were inserted, along with two plain cards, into a mailing envelope for shipment to customers.