Nuts to that. To heck with the acetic acid, man up and use some Hydrochloric *toilet bowl cleaner*, or better yet, some good ole SULFURIC acid on that minor annoyance.
It'll only take a second or two - not days or weeks, and'll only hurt a tiny little tad.

Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good ...