Just a reminder: Postage rates have gone up, so be sure you have plenty of stamps on your return envelopes.

There is a 3/4" maximum thickness that you have to be under, or the envelope becomes a parcel, and rates go up again. Altoids tins don't make it under the 3/4" limit. Be kind to your swapmeisters, and double check your return packages before they go out. The last one I shipped out had approximately half of the packages needing between 40 and 80 cents additional postage each. Not a big deal financially, but it really ends up taking a lot of time at the PO counter.