== All too often it is not corrosion you're seeing but mineral build up. If you run a 50/50 reservoir of vinegar/water once a month it stays clean. Best if you do it from new. It's folly to think anything works flawlessly for 2 years w/o maintenance. While the bottom pin is easy to see and clean, often it is the top needle that clogs. It has a one way check valve but grounds can still get sucked into the first inch or so before the valve. ==