What an interesting question! Thanks for this. Yes, vinegar water is quite safe to use on your skin. In fact, when we do resurfacing laser treatments, we do suggest that the patients wash their skin with vinegar water while they are going through the recovery process. It can be used for pigmentation, BUT it will not affect dermal pigmentation. So it is very important that you find out WHAT kind of pigmentation you have, as I don’t think the vinegar water is necessarily going to “treat” your pigmentation. If you have a pigmentation problem, you need to bear in mind that you also need to go onto products that are going to supress the pigmentation formation from continuing.