This is a great tutorial by metalworker and TV star Chris Hackett. Galvanized electrical conduit is easy to find and dirt cheap, but you can’t really weld it. The galvanization layer–designed to inhibit corrosion–is highly toxic and will burn off in an environmentally uncool manner when welded, and also makes for a “not so great” weld.
Faced with trying to strip off the galvanization, Hackett didn’t want to simply grind it off, which would have been a big pain, particularly when trying to get rid of the galvanization inside the pipe. The alternative? Bathing the conduit in muriatic acid, then counteracting the acid with baking soda.