Some do-it-yourselfers just won’t give up. When my co-worker Nancy’s bathtub drain clogged three weeks ago, she was determined to avoid calling a plumber. Fellow do-it-yourselfers may be familiar with her unclogging-a-drain travails. First, she tried Drano. When that didn’t work, she went to work with a plunger. Nothing. Next she broke out the 10-foot drain snake and worked it seven feet into the pipe. After that failed, she went with repeated pourings of vinegar and boiling hot water down the drain. When that failed, Nancy got serious. This job called for a trip to the local home renovations superstore to buy a 25-foot drain snake. Unfortunately, when she worked the full length into the pipe, she didn’t realize the spool had come undone and she had to reel it in by hand. Blech. The snake did dislodge some clumps of hair but still the drain would not unclog. Another trip to the home renovations superstore to pick up CO2 cartridge to blast the clot out of the pipe with a gust of highly concentrated air. After stuffing a wet facecloth in the overflow pipe, Nancy took aim, blasted away, and finally the pipe was clear. Since the clog was blown into the sewer, it remains unidentified, but her travails were over, and her bathtub drain is now the cleanest in the metro Boston area.