Just that really? I use a purple shampoo and can scratch my head days after I shampoo and underneath my nails will be all purple. I have long thick hair and use quite a high pressure shower to rinse for a couple minutes, but I still can't get rid of the buildup on my scalp. I've washed my hair earlier today and shortly after was fiddling with mg hair and scratched my scalp again and there was loads of moist shampoo buildup still on it. Without using my razor sharp nails and feeling like I'm cutting my scalp every time I scrub, btw can I get rid of the buildup?