I wouldn't really bother. I usually gather GC supply/provisioning stuff anyways. Handing them all HQ will net twice the rewards, can sell/npc or even use them for crafting. Plus I will always need GC seals for those 2 star mats or even sell them since they are quite expensive. And I do that daily while digging for TH maps same time, the challenge log would finished real quick anyways. Win - win. lol