Okay, my dreads aren't /that/ old—just four years. I see a lot of advice on here for washing baby dreads, but I'm wondering how to keep my old, knotted dreads clean. 80% of my hair is dead and dry (as far as I understand), and doesn't really need cleaning like my oily roots do. Currently, I wash my dreads every week with Dr. Bronner's, but I'm afraid of the effect that too much harsh cleaning will have (I was pulling little dead tufts out of the end of a dread the other day!). The simplest solution, I think, is to wash the roots weekly... and the rest of them monthly or bi-monthly. But do you think I ought to wash them less overall?
My dreadlocks are 6 years old. I apply shampoo to my scalp and make sure it gets all over my head and then I rinse. The rinsing water soaks the soap down over and through the dreads and then I just spend a while rinsing and squeezing them. I'm pretty rough with them but I've never had any fear of breaking them, they're made of tough stuff. I'm more worried about not rinsing thoroughly enough.
My dreads aren't nearly as old but honestly I figured I wash them the same as I do now. Once to twice weekly with exfoliating gloves. I apply shampoo on my scalp, use the gloves to really scrub my scalp clean( don't worry it doesn't hurt). Then I rinse with the power setting, then turn it pack to the other setting and wring them like a cloth under the water. Gets my dreads squeaky clean. I would also check online to see how hard your water is. I know that doesn't seem to make any sense but the harder the water, the more buildup you will have. As there are more minerals and such. And with a shampoo like Dr. Bronners you can really have some buildup in your dreads. The softer the water it is okay but try doing a deep cleanse once a month just in case.
Honestly, this is the description of washing long "parallel hair" (and curlies), too. I had a cluster of dreads, not a full head, for a couple years. I treated them like the rest, with extra rinsing. These days, I use shampoo or soap once a week but the scalp gets rinsed daily. If your hair is long enough (dreads or not), you can loosely pull it back so the length doesn't get all wet but the scalp does. Kitchen sink sprayers rock for this.
I've been kinda flaky in the scalp for some months now. My housemate had some Head and Shoulders so I used that and boy did it feel good. Smelled pretty decent too. My locs are not quite 5 years old. Normally I just wash when my head feels dirty about every 2 or 3 weeks. I use dissolved baking soda in a gatorade bottle or diluted Dr. Bronners, or a Bronners bar. The baby mild is great and so is the peppermint. If it's warm out I'll get it wet and scrub around with just water as often as I like. Never underestimate the power of straight water. Otherwise I shower every day and keep it dry when it's cold or damp out. I'm going to do an ACV deep cleanse sometime soon. Haven't done one yet and hope I'm not frightened by what the vinegar looks like after...
Mine are 9 years and down to my ass, I wash mine once every 1 or 2 weeks usicnga bicarb/tea tree/peppermint oil mix and give the scalp a good rub and pour some over the dreads too