Anywhere to trade cartridges?

My system is changing and I have a used EMT TSD-15 that I want to trade for a used Lyra Delos. Is there any board or web outlet that does audio trades? It's so easy to trade a good guitar these days... hoping there's a place to trade cartridges!
Go to Vinylengine's forum and post a WTT post there. In the past I've seen lots of cartridge postings there. As for audio trades in general that is tough. There are many other for sale audio listing sites but not many people willing to trade for stuff.
Bad idea the cartridge could be CRAP!!!!
Thanks for the suggestion. I'll be careful!