the envelope is exposed to is most helpful!! Suggestions to not mail chips in letter size envelopes have been offered here dozens of times but seem to fall on deaf ears. Some people believe that that is the CHEAPEST way to get chip/s from point A to point B until the chip/s do not arrive. Even using the self-sealing cardboard protection in the envelope can be hazardous to the chip/s in the process that you describe. VERY GOOD ADVICE!! Chuck Tomarchio