The kitchen sink was stopped up and rather than call a plumber, which we couldn’t afford, my Mom told me to have a look at it. My plumbing skills were at the time, between none and the recent memory of a couple of This Old House reruns. I squeezed myself into the tiny space under the sink, my knees up against my chest and my head bent at an uncomfortable angle. There were pipes and it smelled a damp and old metal. I twisted my legs to get a better lay of the land, when there came a loud pop…