Yeah
@thistlebloom , I did some research online. If you get the weeds before they are over two weeks old it's supposed to be really effective if you use a stronger acetic acid, like the 20% you said. If killing the top part of the plant will kill it, OK, but that does nothing to kill established perennial roots. That concentration (over 11%) can cause burns or permanent blindness if you're careless handling it. The effects don't last long enough to do much for pH.
The gallon of 5% household vinegar I poured on established Bermuda grass did nothing useful. In the right concentration and used in specific situations it supposedly can work.
I won't be using it.