I've made a snailmail to go to Belgium. I used a brown paper bag to put a lot of snailmail goodies in. I even cut the brown paper bag in half because I didn't have enough brown paper! The end result was quite pretty I thought.
In the paper bag I've put some plastic bags I use at my job. I knew they came in handy one day! I've made magnets, mini envelops, stickers, labels, used old postage stamps and a vintage card.