I frequently reuse bubble envelopes that are in good shape. It is a simple matter to close them up using packing tape. I can remove the old postage, put on new postage, put on an address label and a return address label. It helps keep the cost down on trading chips.

Now the question. Every once in a while I notice that the USPS forgot to cancel the postage stamps on the original envelope that I received. Is it OK to re-use the stamps?