I noticed on my Tefillin that it is a little bit white near one of my Batim. Is this a problem?
Thank you for your question.
The halacha is that the tefillin must be black and even a little bit of the batim may not be white. From a practical angle check to make sure that the white isn’t from dandruff, or some other outside material, and if it is, you can remove it carefully. If it indeed is because the paint of the tefillin has peeled, the tefillin should be taken to a sofer or batim maker, to be repaired. If the white is on the straps, there is tefillin paint sold in many Jewish book stores etc. and you can use that to paint the pats of the straps that have peeled. (Just remember to say “l’shem kidushas tefillin” before starting to color them.) If however the white is on the bayis itself, it is advisable to have a sofer do it, and not yourself. because if it isn’t done correctly, the paint can find its way inside the bayis and can make the parshois black and posul.
O:CH 32-40, 33-3.