Siman 181
Presented here for study, not as a practical ruling. The Shulchan Aruch rules by Sephardi custom, the Rema's glosses by Ashkenazi custom, and the Kitzur follows Ashkenazi custom. For a practical question, ask your rabbi.
א מַיִם אַחֲרוֹנִים, חוֹבָה.
1 Laws of Mayim Achronim. Contains 10 paragraphs: Mayim Achronim (washing after a meal) is mandatory
ב מַיִם אַחֲרוֹנִים אֵין נוֹטְלִים עַל גַּבֵּי קַרְקַע אֶלָּא בִּכְלִי, מִפְּנֵי רוּחַ רָעָה שֶׁשּׁוֹרָה עֲלֵיהֶם; וְאִם אֵין לוֹ כְּלִי, נוֹטֵל עַל גַּבֵּי עֵצִים דַּקִּים וְכַיּוֹצֵא בָּהֶן.
2 Mayim Acharonim should not be done over the ground, rather into a vessel since ruach ra’ah rests on the water; if one does not have a vessel he should wash over small pieces of wood or something similar.
ג אֵין נוֹטְלִין בְּחַמִּין שֶׁהַיָּד נִכְוֵית בָּהֶם, מִפְּנֵי שֶׁמְּפַעְפְּעִין (פי' מְבַעְבְּעִין מִלְּשׁוֹן שְׁחִין אֲבַעְבּוּעוֹת) אֶת הַיָּדַיִם, וְאֵין מַעֲבִירִין אֶת הַזֻּהֲמָא.
3 One does not perform netilah (ritual washing) with water so hot that the hand is scalded by it, because it causes the hands to blister [the bracketed gloss explains: mefa'af'in means meva'be'in, from the language of shechin ava'bu'ot — boils and blisters] and does not remove the grime
ד אֵינוֹ צָרִיךְ לִטֹּל אֶלָּא עַד פֶּרֶק שֵׁנִי שֶׁל אֶצְבָּעוֹת.
4 One does not need to wash any further than the second knuckle
ה צָרִיךְ שֶׁיַּשְׁפִּיל רָאשֵׁי אֶצְבְּעוֹתָיו לְמַטָּה, כְּדֵי שֶׁתֵּרֵד הַזֻּהֲמָא.
5 One needs to lower the tips of his fingers down so that the dirt comes off
ו אִם הַמְּסֻבִּין רַבִּים, עַד חֲמִשָּׁה מַתְחִילִין מִן הַמְבָרֵךְ; וְאִם הֵם יוֹתֵר, מַתְחִילִין מִן הַקָּטָן וְנוֹטְלִין דֶּרֶךְ יְשִׁיבָתָן, וְאֵין מְכַבְּדִין זֶה אֶת זֶה לִטֹּל עַד שֶׁמַּגִּיעִין לַחֲמִשָּׁה הָאַחֲרוֹנִים, וְכֵיוָן שֶׁלֹּא נִשְׁאֲרוּ אֶלָּא חֲמִשָּׁה שֶׁלֹּא נָטְלוּ, מַתְחִילִין מִן הַמְבָרֵךְ.
6 If those reclining [at the meal] are many — up to five, they begin [the washing] with the one who recites the blessing [i.e., the one who will lead birkat hamazon]. And if they are more than five, they begin with the least distinguished [literally: 'the smallest'] and wash in the order of their seating, and they do not honor one another [by deferring the washing, saying 'you first'] until they reach the final five. And once only five remain who have not yet washed, they begin [again] with the one who recites the blessing
ז אֵין מְבָרְכִין שׁוּם בְּרָכָה עַל מַיִם הָאַחֲרוֹנִים.
7 One doesn't make a blessing on Mayim Achronim.
ח יֵשׁ אוֹמְרִים שֶׁמַּיִם אַחֲרוֹנִים אֵינָם צְרִיכִים נִגּוּב; וּלְהָרַמְבָּ"ם מְנַגֵּב וְאַחַר כָּךְ מְבָרֵךְ.
8 There are those who say that mayim acharonim do not require drying [of the hands afterward], but according to the Rambam, one dries [the hands] and afterwards recites the blessing [birkat hamazon].
ט מַיִם אַחֲרוֹנִים נוֹטְלִים בְּכָל מִינֵי מַשְׁקִים.
9 Mayim acharonim — one may wash with any kind of liquid.
י יֵשׁ שֶׁאֵין נוֹהֲגִים לִטֹּל מַיִם אַחֲרוֹנִים; וַאֲפִלּוּ לַנּוֹהֲגִים כֵּן, אָדָם שֶׁהוּא אִסְטְנִיס וְרָגִיל לִטֹּל יָדָיו אַחַר הַסְעֻדָּה לְדִידֵיהּ הָווּ יָדַיִם מְזֹהָמוֹת וְצָרִיךְ לִטֹּל (יָדָיו) קֹדֶם בִּרְכַּת הַמָּזוֹן.
10 There are those who are not accustomed to perform mayim acharonim. And even according to those who follow this practice [of not washing], a person who is fastidious [istenis] and is in the habit of washing his hands after a meal — for him, [his] hands are considered mezohamot [soiled], and he must wash his hands before birkat hamazon.