Many of us take a car to shul to daven in the morning and most of the time we return home and place our tefillin in the cabinet or shelf where we store it until we take it out the next morning. This is all well and fine if that is the case.
What about those of us who fall into one or more of the following categories; 1) The person who drives to shul and then directly to work; 2) The person who drives to shul and then to do errands; 3) The bus and train commuter and 4) The plane traveler.
The person who drives to shul and directly to work may be among those who leave his tefillin in a car. This can also be expanded to the person who after shul spends the day running errands or goes on a day holiday. Tefillin remaining in a vehicle (either in the passenger compartment or trunk) will be exposed to both humidity and temperature extremes. During summer months, a vehicle exposed to sunlight will in all likelihood reach extreme temperatures, which in turn may damage tefillin.
According to an article by Judy Hedding, from About.com: “If you ever park outside during the summer months, your car will heat up quickly. Heat coming in through the windows is absorbed by the interior, and the glass acts as an insulator. The temperature in your car gets up to 200 degrees, depending on the temperature outside, the kind of vehicle you have, and how long it has been in the sun.”
Frankly if I told a person to place his tefillin in the oven for a few hours and heat the oven up to 200 degrees one would say that I am crazy, but that is exactly what one does by leaving them in the car in the summer . The same in reverse is when they are left in the car or even in an unheated shul in the winter when it is extremely cold. One freezes them causing the ink to shatter and split away from the parchment.
Commuters who frequent buses and trains are far less concerned with temperature issues than a general travel issue of what to do with the tefillin in various situations. This is if the tefillin are with you and not in a baggage compartment. The most common problem which occurs is what to do with my tefillin when I have to use the facilities in a bus or train station as well as in an airport. Rule number one is that tefillin and religious articles must be enclosed in two separate coverings. This is known as “kis b’toch kis”. It is commonly found that most people have the tefillin in a second back such as a plastic “zippered” bag or on a talis bag. (There are those opinions with consider the tefillin bag not as a cover for our purpose.) This bag is placed into another type of case or pack. The tefillin in the plastic bag plus the carry base, briefcase backpack etc, which means that we have fulfilled the halachic requirement of kis b’toch kis. This status kis b’toch kis , means if one needs to use the facilities one can take his tefillin into the facilities with him. One should not leave them unattended outside the facilities as the unattended bag may be moved, taken and even destroyed by security personnel.
When traveling in a plane, even on a very short flight during which one does not plan to use tefillin; one should take them on board, and never place them in the luggage. Tefillin which are placed into luggage will be exposed in most cases to a major temperature changes in a matter of a relative short period of time. Luggage is normally stored in an unheated storage area in the plane. An airplane may have a on the ground boarding temperature of 70 degrees F can in a matter of less than one hour go to -70 degrees F when it reaches its cruising attitude. While it may not reach -70 in the storage area it still will suddenly get very cold and can damage both the scrolls and the batim. It can damage the bond of the ink and the bond of the paint. The damage potential is intensified by the fact the plane with on landing go from extreme cold to hot upon landing.
Temperature changes pressure changes and moisture changes can all damage tefillin and with reduce its longevity. The rule with flying is keep the tefillin with you. When you are comfortable your tefillin are comfortable.
For more specific suggests in caring for your tefillin feel free to contact me directly at: firstname.lastname@example.org (Rabbi Moshe Flumenbaum)