My advice would be to stop by your local customs house and ask them what they need in the way of documentation for both the stuff that will travel with you and the stuff you plan to ship for your return. Receipts seem to work for stuff accompaning the traveller up here in Canada and I would imagine that Canada Post (if that's how you ship) won't take your parcel unless it's properly labeled. Watch out for stoves, fuel canisters and such. You might not be able to travel on a plane or ship that stuff unless it is brand new and unused.

But the key is to talk to customs (probably in both countries) if you are unsure. They're the guys who decide who or what gets into our respective countries. Good luck! Al