Shampoo alone doesn't always entirely clean your scalp. Scale and oil build up and need to be vigorously scrubbed out from between the hairs.
As a dermatologist, I do scalp exams all day long and I can tell you that simple shampooing doesn't get our scalps really clean. Using a plastic scalp scrubber when you lather your scalp will help. It will lift scale, dirt and debris up from between your hairs so that your scalp rinses cleaner than ever before. Plus, massaging your scalp with the right plastic scalp scrubber feels amazing! I've found this particularly well-made scrubber that's easy to use - I consider it the 'Cadillac' of scalp scrubbers. You can also use it to distribute gels, waxes and pomades during styling. Trust me, this little known and simple plastic scrubber will be your new favorite thing!