This Clear Lucite Mezuzah Case has a nice clean look and allows you to see the mezuzah klaf. In many cases, there is an halachic advantage to this. The Shulchan Aruch in Yoreh Deah simin 286:5 says that “In places where there are babies with dirty diapers the mezuzah should be covered but in clean places it is better if the mezuzah can be seen.” The reason that it is better if the mezuzah is seen is because seeing the klaf reminds us about the words that are written on it. When we see the klaf, and we think about the words that are written on them, it reminds use to keep Hashem and the mitzvos on the forefront of our minds. Another advantage of clear mezuzah cases is that it is easy to tell that the mezuzah is in right side up because you can see the name of Hashem written on the back of the mezuzah klaf. Using a clear case also makes it nearly impossible to put up an empty mezuzah case. I am familiar with many situations that empty mezuzah cases were up on the wall and people were under the assumption that there was a mezuzah in the cases. Recently, I checked mezuzos at an apartment that had 6 mezuzos up but four out of the six cases were empty. The two cases that were not empty were clear!
Situations that are not good for clear mezuzos.
Even though clear mezuzah cases have some advantages, there are some situations that specifically call for mezuzah cases that are not clear. If a mezuzah needs to be placed inside a room that is shared by a husband and wife, the mezuzah case should not be clear. This is most common with walk in closets that are often found in master bedrooms and other doorways within master bedroom suites. The main doorway mezuzah to a master bedroom can usually go in a clear case since it is almost always located outside of the room. Most bedroom mezuzos will be located outside the bedroom but keep in mind that in finished basements mezuzah often need to go be placed inside the bedroom because the doors sometimes open out into the basement, with the door itself occupying the normal location of the mezuzah every time the door closes.
Clear Lucite Mezuzah Case are not appropriate for outdoor use because the two piece case allows water to seep in through the back. People ask me if it’s okay to use a two piece case in a protected place. I tell them that sometimes it works out and sometimes it doesn’t. I definitely don’t recommend using clear plastic cases or two piece cases, and for sure not both of those characteristics together. If you need to use a clear or two piece mezuzah case outside, it helps a great deal if the mezuzah has been waterproofed in plastic tubing and sealed with a heat sealer. This is the process that I use in my work to insure that outdoor mezuzos will be as waterproof as possible. The bottom line is that water tends to find its target. Sometimes an amount of water so small that it doesn’t even cause the letters to smear, can nonetheless cause a layer of mould to spread out on all of the writing. By the way, if you see a mezuzah like this the best thing to do if it is dry is to take something soft and completely dry like a velvet yarmulke and gently try to wipe the mould away. more than likely it will come off right away with very little effort. By definition, a clear mezuzah case can not be sun proof. If you put a clear case outside in the sun, you basically made a tiny greenhouse that gets very hot. If you do that every day to a mezuzah, over time it can burn beyond the parchment beyond recognition. The sun is damaging to mezuzos in any kind of clear case even if it is completely waterproof. If it must go outside, try to find a very sheltered spot that receives no direct sunlight.