I have had many bad experiences with people mailing old chips in a plain envelope. People that should know better. No matter what kind of cardboard buffer you put around the chip it's often no match for the Post office sorting machinery. They get whipped around circles and the envelopes get bent. Chips don't bend very well. Bubble envelopes get treated differently. Old clay chips **"ABSOLUTELY"** must be mailed in a padded box or bubble envelope. Saving a little money up front does nothing but cause grief in the end.