For a couple years in high school, I had a really cool math teacher. (Yes, The Great Coin Shortage of the '60s.) She used to be an assembly programmer at one of the Baby Bells, and she had a really great story about an older co-worker of hers.

Many years earlier, the co-worker had been working on a major upgrade for the pay phones around the United States. When it was finished, and tested, it was distributed to payphones all around the country.

As all of you who have programmed assembly can attest, programs take a significant amount of time to write, get complex very quickly, and are difficult to modify. The program had a small bug that was overlooked; The money release, for the collectors, did not work. At the time, the number of payphones, and the scale of the problem drastically reduced the number of coins in circulation for a period of time.

The make a long story (that I never heard in its entirety) short, it took them a week to fix the problem and get everything working, the programmer didn't sleep for days at a time, but he got a phone call from Lyndon Johnson encouraging him to hurry up, because of the coin shortage that it was causing.

Anyways, that's all I know about coin shortages in the 60's.