southlatropical

I work for the US Postal Service in maintenance. I work on the very machines that crushed your seeds. Large envelopes (the size of a magazine) are sent through a machine that uses mostly soft rubber wheels. Your seeds are not likely to be crushed on this one because most of the pinch points are spring loaded and 'give' in order to accomodate mail of various thickness to be sorted. Letter sized envelopes however go through at least 2 machines that use belts which are driven by steel rollers. The envelope is sandwiched between two belts as it travels through the machine. There are many belts inside the machine, and at the begining and end of each set of belts there is a roller on each side creating a pinch point. These machines are less forgiving to thick mail. In any case, always use a bubble envelope. Avoid small boxes (size of a pack of cigarettes for example) and tubular packaging.

Here is an mpeg of the Delivery Bar Code Sorter in operation. This is one of the machines that sorts letter size mail. Notice how fast the mail is zipping through the machine.
http://www.teterboro-online.com/imag.../usps/m538.mpg

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