put loose chips within. Instead, fold them up into a sheet of white paper, taping the paper closed and then placing in the bubble mailer. This is why...

A bubble mailer is also subjected to hi-speed sorting equipment at the post office. This equipment can easily force a chip through the flap-end of a bubble mailer, where the kraft paper is a single layer. Moreover, loose chips will slide around and bang into eachother on the long journey, thereby creating nicks, dings and color transfers (from scraping) to other chips in the mailer.

With regards to the end-flap, I always try to fold the flap so as to add another layer paper at the end. This will shorten the envelop, but at that end (which has the least protection) there will be two layers of paper at the fold, which will double the strength of that end of the mailer.

Jim