Does anyone here use a scrub brush for washing?

Something like this:  https://smile.amazon.com/gp/product/B00VAPP48M/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Is it bad for dreads, or cause more loose hairs than using fingers only? 

I would think that it would make more loose hairs than fingers, but I have no personal experience with dread scrubby devices. Any particular reason you're interested in it?

wouldn't that be the exact same thing as combing your hair while washing it? i think that's its urpose to detangle while washing i cant see any other reason to buy that unless you like spending money on useless gimmicks

that is basicly a comb you add soap to

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My new book Ban The Taboo Vol 1

I read somewhere  that using fingernails to scrub dandruff is bad for your scalp, and finger tips don't always get the job done...

If you are worried about exfoliation, use large grain sea salt (mixed in your shampoo of choice) for some abrasive action! Otherwise, SOME dandruff is normal, you can also use tea tree oil on the scalp to tone down the itch between washes. I use one drop of tea tree oil in each shampoo wash (2x/week) and it helps for me.