thanks @sarah, others! great suggestions.
we wash/reuse plastic bags that "fall" into our possession here at the house.
next time i need to store/maildrop i'll def. use your suggestion of one bag and inner paper bags/envelopes.
i'm also just curious of how to seal paper without fasteners. i suppose i'll give elmers a try...
i already use a LokSac for inside my bear bag. so i guess i could get by with one large bag for storage/mail, and another for "today's" trail rations. a paper envelope with today's gorp, etc in my waistbelt pocket could also work.
re-used mylar bags is an option as well, although how to seal?
(lots of my meals are made from cheese/tomato/bean powders, rice, bits of noodle)
the reminder on oil soaking into paper is actually an interesting one. "oilcloth" actually being semi-sealing.
not all wax is made from oil (eg. beeswax):
you could probably seal those with an iron! although not as airtight as plastic, it might be a good happy medium!