If what smauggie refers to as 'scarce quality material' is listed in the catalogues, it should still go for a good price on
ebay. Many buyers will be interested, provided they can identify the item in their catalogues and see what the CV is. Genuinely rare items will sell for way above CV. For example, a very rare Manchukuo stamp sold for $15,000 recently.
Also, you have the Buy It Now option, so you can set your own price or agree to consider offers.
On the down side, I've had problems selling to China, mostly buyers were claiming not to have received the stamps and were therefore entitled to refunds. So I lost the stamps and the money as well. Material sent to China should therefore be sent with proof of postage or registration to solve the problem.