I don't need to put a Customs Declaration (CN22) on stamp mail orders to EU states, as I'm based in the UK. However, what should I write on declarations for overseas orders (USA/Australia) to reduce the risk of loss but still remain legal?

Surely writing "Mint Stamps" or "Philatelic Material" on the declaration is increasing the risk from "sticky fingers" along the way?

Any recommendations?

write "Printed Matter". Simple and not telling a lie.