 Like I said, it's like an ashtray. That's the only way I know how to... I wonder if it's something in the faucet. Do this. I can't tell you exactly what it is. If it smells like sulfur and it's all over, it's an anode rod. If it's all over, it's probably the tank needs to be drained and flushed and all that. But when you start having one faucet issue...