My business involves mailing goods (stamps) overseas a few dozen times a week.

Australia Post sells two different size It'l REGISTERED pre-paid envelopes good for ANY overseas countries.

They cost about $8 for the smaller one and $15 for the real large one - 250mm x 360mm. Those do not have or require any documentation whatever on them, indeed there is no provision for it. They allegedly only are to contain printed matter material. You may send up to 500 grams in either. No ID check is required.

Anything other than that needs to be sent INSURED mail. You may not any longer REGISTER goods overseas unless you use the pre-paid PO envelopes.

Anything NOT insured and not exceeding 2 Kg weight and not exceeding $A500 declared value weight only needs a green CN22 form. The PO also applies a flouro orange "ID VERIFIED" sticker of outside. This is all due to 9/11 and the Anthrax scare in USA.

The odd thing about our GST is that is does NOT apply to exports. If these 2 Australian stamps which recently sold for $A217,898 where offered in Australia and bought by an Australian, I or seller or Auction would need to charge the buyer $21,788 GST on them.

However if I mailed them via $A8 Registered Mail to a relative in NZ or GB or USA there is no GST applicable as they have been exported. If the Ozzie based buyer then collected them in person from NZ and bought them home, or indeed had them mailed back Registered Post, well... you follow the story.

GST applies on ALL second hand goods. I can sell you a 200 year old letter that has changed hands 20 times in its life and GST applies. In many countries second hand goods are exempt, and most certainly as in UK all antiques are exempt, no matter what they are.