I think we've probably been watching some of the same videos, but they both work. The HCL works faster usually within hours, while the vinegar will take at least overnight, maybe days to work. The vinegar will leave the scale as a grayish-black film that will need some scotch-brite and elbow grease to remove. With either the hydrochloric acid or the vinegar, rinse the part, dry, and apply either oil or WD40 to prevent rust.