When I take off my tefilin shel rosh, I very often notice a significant amount of dandruff (white specks) on the retzuos and sometimes on the box itself. Do I need to be concerned that the retzuos are not black (as required by halacha) or that there is a separation between the retzuos and my head? Or may I assume that I was yotzi even if the retzuos are completely covered in dandruff?
Dandruff on the top of the bayis or retzuos are not a problem, because the tefillin still has its black color to it. Regarding dandruff underneath the bayis and retzuos, l’chatchila try that there shouldn’t be a chatzitza, but if there was dandruff there, you are still yotza.
O:CH 27-4 M:B 27-14, PIskeiTeshuvos 27 ftnt. 60.