The stamp dealers of the older generation had a fair number of odd characters, but none were more odd than Morton Paul Goldfarb. Mort, as everyone called him, went to every auction, every stamp show and no matter where you went, you were sure to see him too. Mort specialized in the stamps of the United Nations and only UN. There aren’t many better UN stamps in which to deal and Mort made a specialty out of buying and selling UN postage. The United Nations postal agency is really not a post office at all. UN stamps are souvenirs and the UN maintains a Post Office as kind of a postal fiction. All letters deposited at the UN Post Office are turned over to the United States Post Office which is required by Congress to handle UN deposited mail. It is another US subsidy of the UN. The USPS provides the service and the UN gets the revenue for the sale of the postage.
But to make the burden on the United State Post Office less, the UN has always restricted how their Post Office could be used. Usually, mail use is restricted to just a few letters per person except for a few hours a week and it is very difficult to send packages. The rules change frequently and it is much harder to send mail through the UN Post Office today than it was thirty years ago and it wasn’t very easy then either. Because of this, older UN stamps (that is postage) sell at very low prices relative to their face value, currently under 20%.
Goldfarb’s angle, and it was perfectly legal, was to provide a mailing service to stamp dealers. He would stamp auction catalog envelopes with UN stamps and take stamp dealer auction envelopes and even auction lot purchases to the UN for mailing. As rules changed and each UN postal patron could mail, say, only fifty envelopes at a time (to discourage the Morton Paul Goldfarbs of the world) he hired a team of street urchins to wait in line with him for a few quarters so that they each could mail their fifty too. He bought up UN postage for 30% (it was a bit better then) of face and mailed New York dealer auction catalogs out for 50%. Everyone won except the USPS which was underwriting the party and the US tax payers who were underwriting the US Post Service.  Collectors got multicolored UN frankings on their auction catalog envelopes and prompt first class delivery of their catalogs. Golfdfarb died about 1990. The rules for UN Post Office use had grown so restrictive that for the last few years of his life Goldfarb had to take out ads in Linns and actually try to sell to collectors the stamps he had been a dealer in all his life.