The shampoo and conditioner I use is sulfate free, but lately my hair still looked like it had buildup, even though I don't use any other products (no hair spray, gel, leave-ins, nothing).. I imagine it's partly the hard water in our town. My scalp was also kind of itchy and my hair looked dull and was tangling a lot.
Anyway I just wanted to share what worked for me. Also, my hair is long, slightly wavy, and color treated with some damage from years of bleaching (I've stopped the bleaching as of 2 months ago but I still color it, dark, with a box color every six to eight weeks).
I googled "natural hair clarifying" and found recommendations for vinegar, baking soda, lemon juice.
I am out of vinegar (hate the smell anyway) but I had baking soda and lemon juice. So, I mixed the baking soda with my regular shampoo, about half and half. Did it right in my palm, and made a paste. Worked it in and all over, including the scalp. Left it there for a few minutes.
I rinsed it really well then I applied straight lemon juice (from a plastic bottle, it was not fresh from actual lemons) all over my hair and squeezed it through. Rinsed thoroughly.
My hair was "squeaky" after the lemon juice.
Then I conditioned it with my usual stuff but I also added about 2 tablespoons of unrefined organic coconut oil into my palm and mixed it with my conditioner. I was kind of scared because my hair is fine and can look oily very easily.
I'm happy to report that this procedure seemed to restore shine and manageability. No more dullness and the coconut oil did NOT make it look oily but it was very soft and smelled great.