acv is apple cider vinegar.
The way I personally do it is I have an empty bottle that is supposed to be for travel shampoo (you can get them in the miniature stuff section at stores where they sell "airline sized" small toiletries. I don't know if UK has the same flight rules that US does, but here you can't have more than 3.4 oz liquid containers when you fly in your carry on, so most stores now have a section of miniature stuff. The bottle I have holds 3.4 ounces, and I just put about 1 tablespoon of baking soda in the bottle, add COLD water, andshake it up so it all dissolves. I add cold water so that when I am putting it on my head I know where I've put it so I get full coverage of my scalp and dreads. It has a little hole opening like a regular shampoo bottle, and after getting my hair wet with warm water in the shower I start from the middle front to the back in a line on the middle of my head, then do one side, then the other. Because of the cold I know which dreads I've covered and which I haven't. Once it's all on there I let it sit for a bit without rinsing and I rinse out the shampoo bottle and put in about 1/4 of the bottle of apple cider vinegar. Again I mix it with cold water and shake it up. (be sure to rinse the bottle in between so no BS reacts to ACV). I set it aside in the tub and massage my BS hair and scalp for a bit then rinse it fully under the now warm shower water. Once fully rinsed I do the same thing I did with BS to my scalp but with the ACV solution. Some people don't like the smell of vinegarbut diluted it really isn't noticable. I also let the acv sort of soak in like I do with the BS and while I'm waiting I prepare tea tree oil solution if I'm going to do it this wash (I wash with bs/acv once a week and follow with tea tree oil once a month). Rinse the bottle first (from the acv that was just in it) and put just 1 drop of tea tree oil (it is quite strong, so one drop is plenty). Fill the rest of the bottle with water and shake to mix. I set it aside and massage my head again before rinsing the ACV out (I do the massages because 1, it feels good and gets the circulation in my head going, most hair people recommend massaging your scalp when shampooing, so I treat this as the same, and 2 because it helps the dreads to tangle up, I think. Some people if you scrub too much or too early (before dreads are formed) you might pull some tangles out, but if you check my profile and pics you'll see I am not worried about losing anything LOL. I rinse out the vinegar mixture from my hair, and follow with the tea tree oil if I'm doing it that shower, and let that sit while I wash the rest of myself. Once I'm done washing I do a final rinse of my hair (and everything else of course) and I'm done.
I feel that using bs/acv is why my hair dreaded so fast. when my hair was still tangling and my dreads were still babies I just would do a bucket style pour and rinse, like most people do, but I was using far more bs/acv for that concoction, and I prefer this method because I know I get full coverage even on the back dreads whick with the bucket style pour I felt weren't getting as clean. Plus I love massaging my hair, and I can feel each dread when I do this to make sure I've removed all beads (sometimes I miss one and find it mid shower).
This is just my method, everyone does it differently. Just rememeber to rinse between each solution and to do a final rinse: BS can be drying, ACV balances that, and tea tree oil is very strong and if you use too much (believe me one drop is potent enough) then you may get over drying from tea tree oil (I never havebut some people are more sensetive to tto than others)
