A short while back someone suggested using pickling vinegar against poison ivy (instead of Roundup). I have a small infestation of poison ivy & I'd like to experiment w/ this less "chemical" (you know what I mean) technique. Can you be more specific? First of all, what exactly IS pickling vinegar and how is it different from regular vinegar (and where do you get it?). And then: Do you spray it? Pour it on? Dilute it at all? Apply more than once? How often? Best to do in the morning or evening? Does it matter? Thanks for whatever advice you can pass along, Wendy