Question:

I gave my tefillin for checking and it came back with a lot of splashed ink on the bottom of the Tefillin? Is it valid? Is this a problem of a Chatzitza?

Answer:

If there is actual substance of ink on the bottom of the tefillin then it should be sanded off using sandpaper, or scratched off using your nails. If there is no substance there but simply a black color of the ink [including if after scratching off the substance of ink the color of the ink still remains], then it is valid. [I would recommend that you inform the Sofer who checked your tefillin of what you have found, and that in the future a more professional job should be done. To note, that if you wore the tefillin in this state prior to removing the ink, then any of the ink removed would need to be put in Geniza.]

Explanation:

A general rule in the laws of Chatzitza is that the mere color of ink is not considered a Chatzitza, and hence certainly the same would apply here regarding the bottom of the Tefillin. Furthermore, regarding black ink on the bottom of the Tefillin one can argue that it is never considered a Chatzitza the same way that is not considered a Chatzitza or addition to the actual Bayis, being that it is done for the sake of beauty, and anything that is done for the sake of beauty to an item is not considered a Chatzitza. Accordingly, some Sefarim even discuss as to why we don’t even initially paint the bottom of the Batim, just as we paint the rest of it, and just as some have the custom of painting also the bottom of the straps, as the concept of Chatzitza does not apply when the ink is applied for beauty purposes. However, in truth, seemingly in our case in which the ink was simply splashed due to sloppy work, and was not intended to be done for the sake of beautifying the tefillin, then perhaps it should be considered a Chatzitza, and hence if there’s any substance of ink it must be removed. Whatever the case, the world custom is not to paint the bottom of the tefillin and hence regardless of whether we consider it a Chatzitza to invalidate the tefillin, it should be removed. To note, there’s a general dispute regarding whether a Chatzitza invalidates the wearing of Tefillin, and the above is written according to the final conclusion that we are stringent in this matter.

Sources: See Chayeh HaLevi 1:7; Piskeiy Teshuvos 27:8 that one is to beware that the bottom surface area of the Tefillin is clear of any Chatzitza, such as stickers paint or ink that has substance, or dirt; See regarding the law of Chatzitza by Tefillin: Admur 27:7; Michaber 27:4; Tur 27; Michaber 27:4; Tur 27 See regarding that the Batim are only painted due to beauty of the mitzvah: Admur 32:60; 33:4; Michaber 32:40; Rosh Tefillin 8; Rambam Tefillin 3:14; See M”B 32:184; Piskeiy Teshuvos 32:65 for further details on this matter; Other opinions: Some Poskim rule that the blackening of the Batim is included in the tradition to Moshe from Sinai, and hence is Biblically required. [See M”B 32:184; Kol Yaakov 32:184-185; Piskeiy Teshuvos ibid]; See regarding that ink is a Chatzitza: Admur 161:5; Michaber Y.D. 198:15; See regarding that mere color of ink is not an invalidating Chatzitza: Admur 161:5; Michaber O.C. 161:15; Y.D. 198:17; Rashba Toras Habayis Haruch 7:7; Rosh Mikvaos 27; Betzel Hachochmah 5:82; Halichos Shlomo 4 Devar Halacha 44; Piskeiy Teshuvos 32:74 See regarding that it is valid even if it has substance if it comes to beautify [or protect the Bayis]: Regarding Netilas Yadayim and Daled Minim: Admur 161:5; 651:4; Michaber 161:2 and 15; 651:7; M”A 161:3; Rashba Toras Habayis Haruch 7:7; Rosh Mikvaos 27; M”A 651:2; Levush 651:1; Sukkah 37a; Levush 651:7; Maharam Shick Y.D. 288 [regarding protection]; Regarding Nida: Michaber Y.D. 198:17; Binas Adam 119:14; Pnei Aryeh 6; Keren Ledavid 45; Taharas Mayim 70:2; Taharah Kehalacha 19:45; Regarding Tefillin: Shevet Halevi 5:14; 8:4; Chut Shani Pesach p. 305; Yabia Omer 1:1-2; Shevet Hakehasi 5:15; Piskeiy Teshuvos 32:74