I was cleaning my pentair water filter and unscrewed the drain plug to get the excess gunk out. When I was screwing the plug back in, I went to hard and the plug broke off. The remaining part of the plug’s thread is stuck inside the tank and I’m wondering if there is any trick to removing that piece. I have the replacement plug, but need to remove the part stuck in the thread. There isn’t enough sticking out to use a tool and it is too slippery to use a hand.