how do i unlock purple scrip exchange?

Lol (I'm new to crafting obviously) I just turned in some crafted gear and got purple scrips, but I cannot exchange them anywhere, and I'm not even sure what search terms to look on google to find the info I'm looking for. Every website listed for "how to unlock purple scrip exchange" on google sends me everywhere but to the right information. UUGGHH!!

thanks

ok i think i figured it out. go to each expansion's city hubs like mordona, etc and then unlock all da quests there and then the purple scraps will be unlawcked

you all may continue fighting. lol