Some of these are artifakes, designed and "aged" to look like real Taino artifacts (especially that jug). This doesn't mean that real artifacts are sold, it just means that people with good intentions might get scammed. There is also a conundrum. Do you buy these up for safekeeping thus contributing to their demand, or leave them and risk the chance they fall into non-Taino hands? I don't even have the answer. It's sickening.
I think one good way would be to write an ebay guide warning people of fake Taino artifacts. This guide should come up on the left hand side whenever someone searches for or encounters taino artifacts. You might even be able to list the names of certain sellers, but i'm not sure ebay's policy on that. One way to get around that would be to list sellers' name on a separate website. Another way would be to question the seller on where they received this item.