Question: Is it appropriate to wash one’s lips or mustache from food residue before bentching?
Discussion: Some Gedolei Yisrael were careful to wash their lips using the water that remained on their hands from the mayim acharonim.79
According to the teachings of Kabbalah, however, one should not use his moist hands to wash his lips.80
Question: Is it necessary to have a designated utensil to pour the mayim acharonim into, or will any utensil suffice?
Discussion: The Gemara81 teaches that mayim acharonim should not be poured onto the ground where people walk because a ruach ra’ah rests upon these waters. Instead, it should be poured into a utensil82 or a sink.83 If a utensil is not available, it may be poured in place where it will be absorbed and not gathered into a puddle.84
Therefore, it is recommended to have a designated utensil for receiving the mayim acharonim and refrain from using it for eating to avoid an issue of ruach ra’ah.85 If an ordinary utensil was used for mayim acharonim, it should be washed out well before using it for eating86 One should also avoid washing mayim acharonim in a sink that has dishes in it.87
Question: What should be done with the used mayim acharonim after washing?
Discussion: When the mayim acharonim is poured into a utensil, there is a discussion among the Poskim about whether the ruach ra’ah remains on the water.88 Lechatchilah, one should be stringent89 and avoid pouring out the water in an area where people walk or onto other dishes.
Some have the custom of removing the utensil with the used mayim acharonim from the table before bentching.90 This is because it is considered disrespectful to say a davar shebekedushah in front of water that has a ruach ra’ah91 or has been used for washing soiled hands.92 Others cover the mayim acharonim but are not particular about removing it from the table.93 Yet, a third opinion maintains that the mayim acharonim may remain uncovered on the table throughout the entire bentching.94
The used water may be reused by another person if he does not have any fresh water for his own washing.95
79 This was the practice of the Ksav Sofer, as cited by his son (Hisorerus Teshuvah 63), and of R’ S. Z. Auerbach, as cited in Halichos Shlomo, Pesach, 9, footnote 382. Their practice is based on a story recorded in Yoma 83b.
80 Kaf Hachaim 181:1.
81 Chullin 105b, codified in Shulchan Aruch 181:2.
82 Shulchan Aruch ibid.
83 A sink is considered a utensil (R’ C. Kanievsky cited in Otzar Hamayim 11, footnote 15).
84 Mishnah Berurah 181:6.
85 Eishel Avraham (Buczacz), Tinyana 4:8.
86 Kaf Hachaim 173:15. There are various customs regarding how many times the utensil should be washed off. Some say three times, others hold four times, and yet a third opinion maintains it should be washed out seven times. See Otzar Hamayim 11:4-5 for an overview of the various opinions.
87 R’ T. Weber cited in Vezos Haberachah, Chapter 14, p. 138. See Otzar Hamayim 11:6 who writes that if one washes in a sink, he should rinse out the sink before placing dishes in it.
88 See Beiur Halachah 181:2, ד"ה אלא .
89 Kaf Hachaim 181:12.
90 Kaf Hachaim 181:8; Ketzos Hashulchan 43, Baddei Hashulchan 10; Shevet Halevi 8, 168:3.
91 See Sha’arei Teshuvah 4:8.
92 See Ohr Letzion, volume 2, 1:6.
93 This was the practice of R’ Y. Y. Kanievsky (Orchos Rabbeinu, p. 162).
94 See Ohr Letzion 2, 1:6; Chai Moshe 181:2, citing Siddur Tzelosa De’Avraham.
95 Shevet Hakehosi 3:81:2.