I was going through some Iranian stamps and noticed that a few had US cancellations. Is this common? Some type of diplomatic usage?
Out of the whole mess of stamps these are the only three that don't look like CTO, but the cancels are US.
Here is one with the Smokey the Bear machine slogan cancel from the fifties.
Here's a picture of the entire cancel, from the DC_Machine_Slogan_Cancels document of the Washington Stamp Collectors Club. In that document they list the earliest known use in DC as Sept 1948 and latest known use as Nov 1955.
Here are two more stamps in the series with Washington DC cancels.
The SON cancel reads May 29th, 5pm, 1954 Washington DC. On the 1R value you can only see part of the word Washington and the year 4. Maybe all three stamps were on the same piece at one point?
If anyone can help out explaining why these Iranian stamps would have US cancels, I'd greatly appreciate it. I didn't think any country allowed use of foreign stamps for postage.