Anytime a person eats bread, he is required to wash Mayim Aharonim before reciting Birkat Ha’mazon. The question arises, are there other situations requiring one to wash Mayim Aharonim, or does this obligation apply only when one eats bread?
The Gemara in Masechet Hulin (108a) establishes that people who had the job of measuring salt were required to wash their hands at the end of the day, after finishing their work. Even if they did not eat anything, they were obligated to wash their hands. The Halacha of Mayim Aharonim was instituted out of the concern that some salt may stick to a person’s hands during the meal, and this salt could endanger his eyesight if he touches his eyes. By the same token, people who handle salt are required to wash Mayim Aharonim to remove the salt from their hands, even if they did not eat anything.
Hence, the Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909) and Hacham Ben Sion Abba Shaul (Israel, 1923-1998) rule that one must wash Mayim Aharonim anytime he eats a salty food. This would apply to salty foods such as pickles, pretzels, popcorn and potato chips.
Which part of the hand must be washed when one performs Mayim Aharonim?
This issue is subject to debate among the Halachic authorities. The Shulhan Aruch (Orah Haim 181) rules that one needs to wash only his fingertips, until the knuckles in the middle of the fingers. The Arizal (Rav Yishak Luria of Safed, 1534-1572), by contrast, held that Mayim Aharonim requires washing the entirety of one’s fingers (including the thumb). Thus, according to this view, one must wash not only the fingertips, but rather the entire length of his fingers, until the knuckles in the middle of the hand. It is proper to follow this stringent ruling of the Arizal, and wash the entirety of one’s fingers, until the middle of one’s hand.
Summary: One must wash Mayim Aharonim after eating bread and after eating any salty food, such as pickles, pretzels and popcorn. When washing Mayim Aharonim, one must wash the entirety of all his fingers, and not merely his fingertips.
