The tighter the locs are, the fewer stray hairs you will have and the smoother the locs will look. Washing locs with the proper soaps and shampoos is essential to keeping them tight. The problem with the majority of shampoos, natural or otherwise, is that they leave residue in the hair after they are rinsed out. You can easily detect this residue by smelling the hair, or your hands, after you have used the shampoo.
If the shampoo has left a scent, it has left residue behind. These residues can cause itching when they build up inside your locs and they can make it hard for thicker locs to dry properly. Above all, the residues act as a lubricant making it very hard for the hair to lock and the locs to tighten. This is why it is highly recommended that you use only residue free soaps and shampoo’s on your dreadlocks.