Red Cross Marking On Covers In WW2

These two images come from a thread that I recently started in the Canadian section of this forum

http://goscf.com/t/84337





They both have a red number and date at the bottom that appears to have been applied by the Red Cross in Switzerland as there is no other link between the two covers.

In the above thread there is some speculation as the to meaning of these markings. I wonder if any Swiss expect here can help with a definitive explanation.

AQ

There is an additional link between the two covers, they both are POW mail. Such mail sent to the Red Cross was handled outside of the UPU Treaty governing mail service between UPU countries. Thus while these covers were handled within Switzerland, by the Red Cross, it was not handled by the postal service. Just like the SS Gripsholm the workers aboard were citizens from neutral countries, primarily Spain and Switzerland. while noted for moving people it also moved mail between combatant countries.

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