Risia Ice Games/Monster coin drop

Blue Ice Game Coin
One of the fastest sources of Blue coins is Zawabi's Revenge; at the end of the first hall, just before the first portal, Elder Fire Elementals spawn infinitely. Do not enter the portal - just farm the hall. You get 4 elementals once every 35 seconds or so - you have to move to trigger them. A +30 (or better!) fire resistance is highly recommended. (Additionally, if you have Dimension Door (or just leave and re-enter the quest), you can farm the main hall for a few White coins, although that takes longer to reset.)