distilled white vinegar will work fine, I don't know how much water and vinegar but an excess won't hurt, you can estimate the vinegar based on its strength and the max expected DMT amount. I just like keeping things to a minimum. whatever amount you decide to use, I suggest dividing it into 2 or 3 parts and doing the backsalting in 2 or 3 runs, the first run will pick up most of the DMT and the second and third one will make sure nothing is left behind and less worries about getting the last drop of the water/vinegar out. use cold water/vinegar and do rolling/swirling instead of vigorous shaking.