ive noticed that one of the main problems with twisting and mixed hair textures is the base getting puffy and then the whole twist falling apart. if you look at people with curly hair's scalp when their hair is very short you can see that the hair shafts lie in every direction and most hairs come out of the scalp sideways instead of straight out like straight hair. the pattern is almost like a bunch of swirls with some people. if you force the hair to go in a different direction than it naturally grows you can get the little bumps so bad your scalp will weep and get crusty like a baby with crib cap. your body's natural reaction to stress on the root is to produce more oil than normal and to become inflamed, tender and itchy.
if you can find some tea tree oil you can make your own spray to keep your scalp fresh by mixing it with water and maybe a little bit of virgin coconut oil and aloe vera juice (you can get those from whole foods or the vitamin store). if you don't have a medicinal herb store near you our local store does online orders - www.herbsandarts.net . i havent looked at their site lately cuz i usually go in person but if you call them they will answer any questions you have and can process your order over the phone. my friend mave is a master herbalist and makes all their herbal extracts, oils and blends. they have dried herbs in bulk if you want to get some oil and make your own herb infused oils also. if you call the store she is usually there or they can tell you when she will be in. the owner Kaywynn has really long dreads too so she might be able to tell you some of the things she uses.
if you want to get the wax and product buildup out you can use baking soda. it completely breaks down grease and bonds to it so it can rinse out but then you should spray on some hemp oil or a little coconut oil mixed with water on the roots so your scalp doesn't get dry afterwards. All the wax and buildup is holding grime, dust and lint in there and your dreads can start stinkin like mildew or rancid oil after a while if you never wash that stuff out. i used to use wax and to get the buildup out i took a whole small box of baking soda, added enough water to make a smooth paste to the point where there was a little bit of water on top and then put it on my hair in handfuls and worked it through each dread. Palmroll and massage it in with your fingertips to get it all the way into the middle. You want to rinse it out really well too because residue will turn white when it dries. Completely soak your hair in the bathtub underwater if you can to get all the wax out of the middle too. If theres a lot of buildup you might have to do it a few times. Your hair will feel squeaky clean when you get all the product out. You can do a coffee rinse afterwards to make your hair shiny again if you want.