I ship up to a few chips in a #10 envelope with a cardboard mailer. I pay for the correct ounce weight and then add the extra for it being non-machinable. I make sure to mark the envelope as non-machinable although sometimes they still run it thru the machine. I also do all of this at home and drop the envelope in the mailbox just to avoid the hassles of dealing with the cage critters at the post office.