One of the few times I tried mailing a chip in an ordinary #10 envelope at the buyer's request . . . buyer said he never got it. No tracking, so I cannot prove a thing. Re-mailed another such chip in an 00 Envelope (with tracking) and it got through fine. Thereafter, if a buyer demands mailing in a plain envelope to save $1.25 or so, I spell out in exquisite detail that I will not be responsible for loss or damage for using that method. Once under a blue moon, a chip in a padded envelope also gets cracked by rough handling (the post office drops a piano atop my package?). But those are old, one-of-a-kind chips that I don't really care about much.