Exchanging dark light, AF and Coil gear on... something?

[Onyxys]

Greetings. Why players can not exchange gear, which they dont need any more for something useful? For example I had DArk light ring and I get in Coil another ring- much more better. Now I need only to throw away dark light ring? Or I bought ring for ToM (375) and ring from Coil is better. Why I can not exchange ToM-ring for something- maybe on ToMs, but these ToMs must be atop of weekly cap. Maybe another ideas. Many players already have a lot of gear, that they dont need

Thank you