I visited the local post office this morning with yhe intention of posting a CD to Hong Kong. I hade expected to have to pay about $20 to ship it as a parcel but was charged only $5.10. The lady on the counter told me that Economy Air for large letters had been reintroduced for many countries. I checked on Australia Post's website where you can find lists of potage options for all the countries of the world listed in alphabetical order. If you are able to find that list you will see that most, though not all, allow for CDs to be posted as large letters (shipping time is 25+ days). Incidentally, if this was not allowed the lady would not have been able to process my Customs declaration on her computer.