There are occasions, e.g. a mezuza in a sometimes-unbecoming environment, in which we're required to cover a holy object with one or two wrappings to separate it from various environmental elements. What are the necessary qualities of these wrappings?

  • Do they need to be opaque? If so how opaque? (At the extreme, would clear plastic work?)

  • Do they need to be watertight or airtight, or can they be porous? If the latter, how large can the holes be? (At the extreme, would a loose net bag work?)

  • Do they need to be durable? (At the extreme, would tissue paper work?)


3 Answers 3


I believe what you are referring to is the concept of kis b'toch kis or a 'pocket within a pocket'. This is a halachic wrapping for words of Torah, tefillin, siddurim, sifrei Torah, etc. being brought into a situation of uncleanliness like a bathroom.

The halachot are as follows (this is all based on learning from my Rabbi, so I don't have sources for you, sorry...):

  • You must have 2 separate coverings aside from the items usual covering (ie. a tefillin bag)
    • An exception to this rule is while traveling, where you may rely on a single covering in addition to the item's usual covering (tefilling in tefillin bag in backpack)
  • One of the coverings may be clear, but one of them must opaque to the point which one cannot make out the text written underneath it.
    • For example in the Yeshiva where I learned the Mezuzot are all in clear plastic cases, but the ones which are in eye-shot of the bathroom are also wrapped in printer paper so as to prevent them from 'seeing' the bathroom.
  • There is no distinction as far as porous vs. non-porous for this matter. Regarding the size of the holes, this would relate to the clear/non-clear issue and perhaps to whether or not it is majority holes or majority material.
  • As far as I know there is no qualification of durability.

There is another situation to which you may be referring to, and that is burial of semi-geniza items (ie. photo-copies of Torah sources, but not things written on parchment) or items that may not be thrown out (such as a kezayit of bread). Regarding these items they should be double wrapped if using a porous material (such as paper or a napkin) and may be single wrapped if using a non-porous material (ie. a plastic bag). (Again this is learned directly from my Rabbi, so sorry for the lack of sources...)

  • Oral tradition is a source. Even more so if you're willing to name your Rabbi.
    – Isaac Moses
    Jul 29, 2011 at 1:22
  • I will, bli neder, try to confer with him to verify that what I am saying here is exactly as he intended and then post. Thanks for the tip.
    – Adam Simon
    Jul 29, 2011 at 1:24
  • In general, for both questions and answers, the more information you can provide about where your information/curiosity is coming from the better, even if it's as simple as "my mother showed me ..." or "someone in shul asked me ..." It's up to readers to determine the usefulness of your information, and the more information about its provenance, the better they can make that determination.
    – Isaac Moses
    Jul 29, 2011 at 1:28

I believe the answer to your question depends on the context and requirements.

For cooking for example, it can't be porous, for tumah, it can, but it has to be a Kli. For a mezuzah it can be transparent, but has to be weatherproof, for Challah it can't, as it has to be hidden. For "coverings" like the shemah or tachanun all you need is something physical of any nature that isn't your body. But you asked about a wrapping, not a covering.

Sof'b'sof, I imagine that a halachic wrapping is anything which fulfills the requirements of the wrapping. That is, if the purpose of the wrapping is to prevent sight, then it just has to be opaque without giving a hint as to what is behind it. If the purpose of the wrapping is to keep it clean, then it must prevent dirt, (such as saran wrap). However, I defer to any brisker types out there, who might have a particular hebrew or aramaic word for wrapping and what it is defined by, and which mitzvot it applies to.

  • 1
    Thanks for breaking this up for us. Could you provide sources for any of these?
    – Isaac Moses
    Jul 7, 2011 at 18:00
  • Unfortunately, I am a walking version of learning via the oral tradition, my source are various teachers from various shiurim :(
    – avi
    Jul 7, 2011 at 18:08
  • To your last point, I'm asking mostly about where we want to protect a holy object from its environment, which only applies to one or two of your examples - mezuza and possibly tumah.
    – Isaac Moses
    Jul 7, 2011 at 18:17
  • Well for cooking, we want to protect the food from its environment as well. We want to make sure no non-kosher tastes enter into the food, because of the environment it is in.
    – avi
    Jul 7, 2011 at 18:19
  • Food (even Kosher food), in that sense, isn't a holy object. The whole topic of mixtures is distinct from the topic of protecting holy objects.
    – Isaac Moses
    Jul 7, 2011 at 18:21

The MB in 40:7 explains why one cover at least, must be opaque. He says that there needs to be 2 covers, AND, it must not be able to be seen. Therefore, a glass of clear plastic would be good for one cover, but you can’t use it for both, since it would be able to be seen through them:

ואם על המזוזה יש כסוי זכוכית אף שהמזוזה נראית מתוכה אפ"ה נחשבת כסוי אחד ודי בפריסת סודר על המזוזה דהא עתה לא מיתחזיא וכ"כ הדה"ח. אבל לכו"ע לא מהני אם יכסנה עוד בזכוכית מלמעלה אע"ג שמכוסה בשני כסויין דהא המזוזה נראית מתוכן

The MB IN 240:25 he explains that a porus Mechitza is a machlokes, but in the Shaar Hatzion 240:12 he seems to indicate that the reason is due to the fact that it only separates the room and makes it as a different place. However, the issue of covering is not accomplished. So in a case where only a Mechitza is required, it would be fine, but for a covering, it’s unacceptable -

כתב המ"א אם יש נקבים וחלונות במחיצה כעין סריגה אסור עד שיהיו הספרים מכוסים מן העין שאין נראין ובספר נהר שלום מפקפק על דבריו וכן בספר תוספת ירושלים ובמקום הדחק יש לסמוך ע"ז אכן לכתחלה טוב לכסות שלא יהיו הספרים נראי

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