Amoco ran a sweepstakes promotion three years in a row, giving away various prizes including cash and a Ford Mustang. Since you had to turn in the stamps to claim your prize, these issues can be very hard to find.
These tiny stamps came in panels of three and were to be stuck on a saver sheet to collect your prize.
Rules and Saver Sheet
Bob Lilly Complete Stamp Sheet
1967 American Oil Stamps
Panels of three were used again but this time the stamps were action shots of NFL players.
1967 Saver Sheet
1968 American Oil Mr. & Mrs.
In 1968 Amoco used a different approach for their sweepstakes promotion. A combination of both halves of the game pieces were required to claim your prize. In addition to the Mr. & Mrs. cards, another promotion was added in which you were required to enter the correct score to the Super Bowl on the corresponding game piece with the correct teams in the big game.