Okay.. I was selling like 14 mets, and some guy was buying them all. I noticed they were flashing in my invetory everytime he bought one. So I waited until he bought it, and caught it the moment it flashed. And surpisinly enough. I sat it down in the invetory and it stayed. Now.. I tried to put it back up to sell and it dissapeared. I'm not sure what would happen if you sat it down and closed your invetory. Or maybe tried putting it in your warehouse. I haven't been able to catch them again. But if someone could investigate this, It might lead to something great.