If I understand correctly, you don't mind players getting lots of iron, but the problem is when they sell it and get lots of money. It wouldn't be right to remove iron from the market, as this would also affect legit miners, but iron farms only drop ingots, so why not just remove iron ingots from the market, then miners can still sell iron ore? Also, if you don't like this idea, (I'm sure you have heard it a million times...) remember, I'm still a developer! Much more experienced now, too! I could make a plugin for you that stores locations of iron golem deaths, and I could figure out a way to get distances from other iron golem deaths to track hot spots. =)