Board Thread:General Discussion/@comment-31991905-20170605223753/@comment-25730832-20170606001718

You CAN farm EO maps for screws, but that process comes a long time later. One medal can be traded for 4 screws; however, you should worry about that after you complete the Kai-ni process of ships that requires Blueprint (4 medals) first.

I'd say keep the medals for now. Use it to get some blueprint for kai ni. Screws can be dealt with later through other means.