They are drop by sickened humans in Minister Cho's Estate. But i don't know how to add this information correcttly in this page. Feel free to add it.
Worthless?[]
These only trade for the first available AL helms. However, Guardsman Ayoki collects three Copper Crimson Skull Coins in exchange for headgear with higher AL. The coins are easier to obtain, and the collector is easier to reach. Forgotten Trinket Boxes seem rather useless in this case. Vyldan