The obligation of Mayim Aharonim, washing one’s hands after eating a meal, applies even nowadays, and applies to both men and women. (In a different edition of Daily Halacha, it was mentioned that one must wash Mayim Aharonim after eating a meal with bread and after eating salty foods.) Mayim Aharonim requires washing the full length of all five fingers, until the knuckles where the fingers connect with the hand.
If a person forgot to wash Mayim Aharonim before he began reciting Birkat Hamazon, and during Birkat Hamazon he noticed that his hands are dirty, he must interrupt Birkat Hamazon to wash Mayim Aharonim. He then resumes his recitation of Birkat Hamazon.
One should wash Mayim Aharonim with cold water. Warm or hot water should not be used, as it does not effectively remove the filth from one’s hands.
The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909) writes that when washing Mayim Aharonim, one should use as little water as possible. The water used for Mayim Aharonim becomes Tameh (impure) and enters the domain of the Sitra Ahara (forces of impurity). One should therefore minimize the amount of water to whatever extent possible, in order to minimize the amount of water given over to the Sitra Ahara. The Ben Ish Hai adds that if one’s hands are soiled and require a large amount of water to become clean, then he should wash his hands thoroughly to clean them, with the intention that he will continue eating after washing. Then, after rinsing his hands, he should eat a small morsel of food, and then wash Mayim Aharonim with a small amount of water.
After one washes Mayim Aharonim, he may not speak until he recites Birkat Hamazon.
It is preferable not to leave the water used for Mayim Aharonim on the table during Birkat Hamazon. It is customary to either remove the water from the table or to cover it.
If one has water available, he should use water for Mayim Aharonim. If not, then he may use any beverage, even seltzer, soda and the like, with the exception of wine.
It is customary to announce before washing Mayim Aharonim, "Mayim Aharonim Hoba" ("Mayim Aharonim is obligatory"). By making this Halachic statement before washing Mayim Aharonim, one ensures to include words of Torah at the meal. Furthermore, the Ben Ish Hai writes that there are Kabbalistic reasons for making this declaration before washing Mayim Aharonim.
Finally, the Kaf Ha’haim Palachi (by Rav Haim Palachi of Turkey, 1788-1869) writes that one should not use for Mayim Aharonim water from which one has drunk. Thus, a person should not use the leftover water from his drinking glass for Mayim Aharonim.
Summary: Both men and women are obligated in Mayim Aharonim. One should wash Mayim Aharonim with cold water (other beverages, except wine, may be used if no water is available), and after one washes the water should be removed from the table or covered. One should use as little water as possible for Mayim Aharonim. If one forgot to wash Mayim Aharonim and during Birkat Hamazon noticed that his hands are dirty, he should interrupt Birkat Hamazon to wash his hands. It is customary to declare "Mayim Aharonim Hoba" before washing Mayim Aharonim.
