By: Rabbi Ari Enkin
It is generally understood that for something to be deemed a “vessel” from the perspective of halacha, it must be solid, intended to be permanent or otherwise long-lasting, and robust enough to be continually re-used. Furthermore, we are also taught that the goblets used for Kiddush, Havdala, and Birkat Hamazon must be dignified and solid utensils. As such, it is considered by many authorities to be unbecoming to use throw-away items for such mitzva related uses. So too, the goblet used when reciting the Birkat Hamazon over wine, as is often done when ten or more men have eaten together, must be completely whole without any dents or cracks and able to stand on its own. For those who use stemmed goblets for Kiddush and the like, it is important to ensure that the stem and other base components are complete and undamaged, as well.
Some authorities are of the opinion that disposable goods don’t qualify under the above mentioned guidelines since they can be destroyed with little force and were not intended to be durable. An item which lacks these features is considered similar to being “broken” or “damaged” from the perspective of halacha. Others reject this comparison and consider new and completely whole disposable goods identical to regular utensils for all mitzva purposes. It seems to be the consensus, however, that when a proper and beautiful wine goblet can be easily obtained, one should not use a disposable one.
Similarly, it is considered to be of utmost importance to ensure that objects used in the course of a mitzva be as beautiful as possible. This shows honor to the mitzva one is going to perform. As such, some authorities insist that reciting the Kiddush over a cup made of paper or plastic which is intended to be thrown away after use is disrespectful to the honor owed the mitzva of Kiddush.In the event that no other goblet is available however, there is certainly room to allow the use of such cups. The same rules apply in a number of other situations as well, such as when one recites the Birkat Hamazon over a cup of wine. There too there is a requirement that the cup be beautiful.
As previously mentioned, the hand washing which is done before eating bread must be performed with the assistance of a vessel. The same issues raised concerning the use of a disposable vessels for Birkat Hamazon and Kiddush are equally applicable to the suitability of using them for washing one’s hands. Here too, while it is ideal to use a permanent and impressive looking cup for this purpose, one need not object to the use of a disposable cup when nothing else is available. While it is essential that the cup used for Kiddush and the like be able to stand on its own, there is no such requirement concerning the cup used for washing hands. Even a cone shaped cup would be permissible.
Even though there may be grounds to disqualify the use of disposable goods for a mitzva,the situation might be somewhat different today. This is because the disposable goods which are used today are not like the ones that were used in the past. The high quality products that are available today may in fact not be considered “disposable” from the perspective of halacha. Some authorities are of the opinion that today’s disposable dishes really aren’t exclusively disposable any more. Although they are inexpensive and easily replaceable, they are often manufactured to be quite sturdy and even attractive. Many people wash out and reuse such “disposable” goods several times before actually throwing them away. Indeed, some authorities recommend that in the event that one is forced to use a disposable utensil for a mitzva, one should wash it out and re-use it several times in order to symbolically afford it a more permanent and dignified designation.
With disposable goods now available in a variety of colors and sizes, not to mention durable and long lasting, they should no longer be considered the unbecoming tableware as perhaps they once were. It is common for even very prominent people to be served in such vessels and even at elegant affairs. As such, although it is certainly ideal to use the most beautiful cups possible for any mitzva, the modern day disposable goods should be recognized as halachically acceptable for any purpose.
 Rambam Keilim 5:7
 O.C. 271:10
 O.C. 183:3
 Magen Avraham 183:5
 Igrot Moshe 2:75
 Tzitz Eliezer 12:23. See Shraga Hameir 1:55 for different views
 Igrot Moshe O.C. 3:39, Mishna Berura 183:11
 Shemirat Shabbat 2:47:11, Igrot Moshe O.C. 2:75
 Igrot Moshe O.C. 3:39, Tzitz Eliezer 12:23, Shraga Hameir 1:55
 O.C. 183:3
 Shaarim Metzuyanim Behalachah 40:3
 Minchat Yitzchak 1:23, Mishnat Yaakov 1:6:8
 Be’er Moshe 5:55, Tzitz Eliezer 12:23
 Minchat Yitzchak 1:23, Be’er Moshe 3:55
 Rabbi Shlomo Zalman Auerbach cited in Shemirat Shabbat
 Tzitz Eliezer 12:23, Az Nidberu 6:49