First always check the prices of your greens incase you got some expensive transmog gear then determine If you need Expulsom for crafting if so keep all greens if not check prices of Gloom Dust on your server/ See what greens are selling for and either disenchant for dust or sell the greens in bulk
To sell bulk greens you just spam chat in game usually saying x greens vs x gold or just search for someone buying bulk greens on your server, you can also use tsm and setup a auto post to quick post all your greens bit annoying to setup but once you have it your good.