Whether off on his travels or at home, Folon enjoyed writing to his loved ones. Wherever he found himself, he bought postcards and went to the post office to choose stamps. He then entertained himself illustrating the envelopes or postcards he would send to his family and friends. He let his imagination run wild, repurposing them and enhancing them, sticking collages on them and drawing or painting on them. This was so important to him that he got his artist friends involved, too. These included Pierre Alechinsky and Milton Glaser, whose touch can be seen on a few envelopes.
A book published in 1975 features the envelopes and postcards sent to his friend Giorgio Soavi, the artistic director at Olivetti: Folon, J.M., Lettres à Giorgio, 1975, Chêne-Alice Editions.