When a Saturday DIY Fix Turns into a Stubborn Gurgle: Mark's Story

https://www.mediafire.com/file/ral453vfzoe2dc6/pdf-36489-67697.pdf/file

Mark had always liked to tinker. One Saturday morning he noticed his kitchen sink draining slower than usual. He grabbed the familiar green bottle of chemical drain cleaner from under the sink, poured it down, and went on with his day