The laws of the liquids used for Mayim Achronim?
What liquids are valid? All liquids are valid for Mayim Achronim, including oil, honey, and milk, with exception to wine. [Nevertheless, initially if water is available one is to use water for Mayim Achronim. However, in a case that water is not available, one may use other liquids, and if even other liquids are not available, one may use wine.]
Water that is invalid for washing for bread: Water that is invalid for washing for bread, such as water that had work done with it, or has changed color, is nevertheless valid for Mayim Achronim.
Hot water: Hot water is invalid for Mayim Achronim. It is disputed amongst the Poskim as to whether the invalidation applies to hot water of any temperature, even less than Yad Soledes, or only to hot water that is Yad Soledes [110 Fahrenheit]. Practically, one may be lenient to use hot water that is less than Yad Soledes.
How much water must one use for Mayim Achronim? There is no minimum amount of water required for Mayim Achronim, unlike other washings such as for bread, in which a Revius is required. [On the contrary, since the water belongs to the side of impurity, one is to use a very minute amount. Thus, if one’s hands are overly dirty, or one also desires to wash his face from the food, he is not to consider the water as Mayim Achronim, and is to wash regularly, eat something and then wash Mayim Achronim with a minute amount of water for the Mitzvah.]
One may use alcohol for Mayim Achronim?
This follows the same law as other beverages, which are not to be used unless water is not available.
May one use saliva for Mayim Achronim?
Saliva is not valid for Mayim Achronim.
 Admur 181:8; Michaber 181:9 “With all liquids”; Rama 173; Raavad in Tamim Deim 66; Meiri Beis Yad 14; Ketzos Hashulchan 43:2
 The reason: All liquids are valid as they all equally accomplish the removal of the toxins from the hands. However, wine may not be used being that it is considered a Chashuv beverage. [Admur ibid]
 P”M 181; M”B 181:20; Ketzos Hashulchan 43 footnote 6; Shulchan Hatahor 181:4; Poskim in Kaf Hachaim 181:24
 See Kaf Hachaim ibid that some Poskim permit using wine
 Admur ibid; M”A 181:7; Elya Raba 181:3; Raavad in Tamim Deim 66; Meiri Beis Yad 14; M”B 181:21
Other opinions: Some Poskim rule that the water of Mayim Achronim must be valid for washing for bread. [Shiltei Giborim, brought in Beir Heiytiv 181:8 and Shaar Hatziyon 181:31]
 Admur 181:3; Michaber 181:3; Chulin 105a; Ketzos Hashulchan 43:3
The law today: Perhaps in the event that one’s hands are clean it is permitted today since we no longer have Sodomite salt, to wash with even hot water. [Ketzos Hashulchan 43 footnote 11]
 Admur ibid; Michaber ibid; Chulin ibid
The reason: Hot water expands the skin and does not remove the impurity and filth. [Admur ibid; Michaber ibid] However one may use hot water for washing hands for bread.
 Some Poskim rule that the above law refers to water that is Yad Soledes. [1st opinion Admur ibid; Michaber ibid “With water that the hand gets burnt with”; M”A 181:3] Other Poskim rule that even warm water is forbidden. [2nd opinion in Admur ibid; Rashal, brought in M”A ibid, that the water must be cold]
 The reason: As Safek Derabanan Lekula. [Admur ibid]
 Admur 181:4; Elya Raba 181:3; Beis Yosef 181; Rashal Chulin 8:10; Raavad in Tamim Deim 66; Meiri Beis Yad 14
Other opinions: Some Poskim rule one is to use a Revius of water. [Gra, brought in M”B 181:19; See Kav Hayashar 13 and Piskeiy Teshuvos 181:9]
 Chida in Hagada Shel Pesach; Ben Ish Chaiy Shelach 9; Kaf Hachaim 181:6
 Minchas Elazar 3:54; Pnei Meivin O.C. 32; Piskeiy Teshuvos 181:12