Siman 181 Seifim 10
1. Mayim acharonim is obligatory.
2. Mayim acharonim should not be done over the ground; rather it should be poured 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.
3. One may not wash with hot water that would burn one’s hands since it inflates the hands (the meaning is מבעבעין related to the term שחין אבעבועות) and does not remove the filth.
4. One need not wash any further than the second knuckle.
5. One should slant his finger’s down so that the filth would fall off.
6. If there are up to five people at the table the one who will recite birkas hamazon should wash first. If there are more than five people the washing begins with the one of least stature and then they wash according to the way they are seated without honoring someone to wash first until they reach the last five people. Once only five people remain the one who will recite birkas hamazon should wash.
7. There is no beracha to recite on mayim acharonim.
8. Some maintain that it is unnecessary for one to dry his hands after mayim acharonim but according to Rambam one must dry his hands and then recite birkas hamazon.
9. One may use any liquid for mayim acharonim.
10. Some do not have the custom to wash mayim acharonim. Even those who have that custom if one is delicate and accustomed to wash his hands after a meal so that he considers his hands filthy, he must wash his hands before birkas hamazon.