Birkat Hamazon - Mayim Acharonim

There is a practice in many Orthodox communities to wash the hands before reciting birkat hamazon. This practice is called mayim acharonim (final waters). It is held that this, though a chovah (duty), is not a mitzvah (a commandment), as the practice was instituted for health reasons (specifically, to avoid the danger of touching the eyes with harmful salts). A special ritual dispenser can be used to dispense the water, but does not need to be. Although the practice is based on a ruling recorded in the Talmud, whether or not this ruling is still binding is a matter of dispute among various Orthodox communities, given that the practice of eating with knives and forks seems to remove the practical reason for it. Some practice it as a binding halachah, others as an optional custom, and others do not practice it at all. Among those who do practice mayim acharonim, the majority simply pour a small amount of water over their finger tips (note that according to the Mishna Berurah, this does not fulfill the terms of the obligation at all but according to the Kitzur Shulchan Aruch(43:1) one "need not wash the entire hand. It is sufficient to wash until the second joint of the fingers", while a minority, usually Yemenite Jews or related groups, will wash up to the wrist. One should not pause between the washing and saying birkat hamazon.