A person who prays must be in a state of purity. It is therefore a mitzvah to wash one’s hands before engaging in prayer. However, a distinction is made between a situation in which a person knows that his hands are unclean, and one in which he does not know if his hands have been dirtied.
For example, if one knows that his hands are dirty because he relieved himself, or touched normally covered parts of his body which have become soiled from perspiration, he must wash his hands before praying. According to many poskim, he must recite a berachah on this washing even before Minchah and Ma’ariv (Rambam, Rosh, Gra). However, the accepted custom is to recite a berachah solely on the washing before Shacharit, because when a person awakens in the morning, it is as if he is created anew. Regarding washing one’s hands before Minchah and Ma’ariv, even one whose hands are dirty does not recite a berachah (according to the Rashba, see further in this book 8:1).
In any case, according to all opinions, a person who dirtied his hands is obligated to wash them before he prays. L’chatchilah, he should pour water over his entire hand with a vessel. However, if he does not have a vessel, it is sufficient that he rinse his hands with water from a faucet.
In order to wash his hands before praying, if there is no water close to him, he must trouble himself and walk up to the distance of a mil, which is approximately a kilometer (960 meters or approx. .597 miles). However, if, as he is walking, the designated time for prayer will pass, or he will miss the opportunity to pray with a minyan, he can rub his hands with sand or on his clothing, in order to remove any trace of dirt from them – and then he may pray (Shulchan Aruch 92:4; Mishnah Berurah 92:20).
Regarding someone who does not know if his hands are dirty, since he doesn’t remember if he touched the parts of his body which are normally covered, the poskim are divided as to whether or not he must wash his hands before prayer. Hence, if there is water available, he should wash his hands. However, if there is no water near him, he does not need to wash his hands and he may rely on the poskim who maintain that it is only necessary to wash one’s hands before prayer if they are unclean. To be certain, one should rub his hands on his clothing (Shulchan Aruch 92:5, 233:2; Mishnah Berurah 92:26; Bei’ur Halachah s.v. “V’im”).
Concerning one who relieves himself, washes his hands in his house, and afterwards is careful not to touch the parts of his body which are normally covered, and then goes to synagogue, he need not wash his hands again before praying. Similarly, if someone who arrives at synagogue to learn and pray washes his hands before learning, and is careful not to touch the parts of his body that are normally covered, it is not necessary to wash his hands again before praying.
. According to the Rishonim who maintain that it is necessary to wash one’s hands with a berachah before all prayers, one must use a washing vessel, for the Chachamim instituted the berachah of washing for prayer following the example of washing before a meal (see Rambam Berachot 6:2; Ra’ah, Rabbeinu Yerucham, and Rosh who are brought by the Beit Yosef; see Shulchan Aruch 4:7 as well). In practice we do not recite the “Al netilat yadayim” berachah before Minchah and Ma’ariv, because the rule is that when there is doubt regarding the recital of berachot, we are lenient and do not recite them (safek berachot l’hakel). Nevertheless, it is the opinion of most poskim that it is correct to be stringent and perform all the other requirements connected to washing one’s hands before a meal. Therefore, it is proper for a person whose hands are dirty to wash them with a vessel. Even a person whose hands are not dirty can enhance the mitzvah by washing them with a vessel, for perhaps the Rishonim who maintain that even a person who does not know if his hands are clean or dirty need to wash them, require using a vessel designated for pouring water over the hands. However, those who follow the lenient opinion and wash their hands without a washing cup have on whom to rely, for even concerning the washing before Shacharit, the use of a vessel is only l’chatchilah. All the more so before the other prayers, when one does not recite a berachah on the washing, and even more so when one does not know if his hands are dirty.
.If he is walking on his way and within the four mil ahead of him there is water, he must walk to it and only afterwards pray. The Shulchan Aruch 92:7 writes, “A dirty area is [defined as] the [normally] covered parts of a person’s body, because they contain beads of sweat. For instance, scratching one’s head [is considered touching a dirty place].” This refers to rubbing the roots of one’s hair, but if someone only touches the top of his head, he does not need to wash his hands (Shulchan Aruch HaRav; Mishnah Berurah 162:58, 164:10). Kaf HaChaim 4, small paragraphs 75 and 98, is lenient even if one scratches the roots of his hairs which are not covered with a hat, because there is no sweat there. Tzitz Eliezer, part 7, 2:14 concludes that if he washed his head and his hair is clean, even a person who scratches the roots of his hairs does not need to wash his hands.
Concerning a person who touches other normally covered parts of the body: if his body is washed clean and does not have beads of sweat on it, the Acharonim disagree as to whether or not he must wash his hands. Eshel Avraham Butshatsh 4:21 is stringent, and Yabia Omer, part 5, 1:4-5, cites poskim who are lenient. According to the Minchat Yitzchak, part 3, 26:10, those who wear short sleeves and touch their skin above their elbows need not wash their hands because that part of the body is not one which is normally covered. However he also refers to the Chazon Ish who writes that this place is defined as a normally covered part, and that people who wear short sleeves should not be taken into consideration. Mor U’Ketziah, section 4 writes that for those who wear short sleeves, above one’s elbow is not considered a normally covered part. And that is the custom.
The Rama 92:7 maintains that earwax is considered a covered part and one who touches it is obligated to trouble himself to walk up to a mil to wash his hands. The Mishnah Berurah writes that the Gra is lenient concerning this. However, Otzrot HaGra, p. 219 interprets the Gra differently, saying that he is not lenient regarding this. Similarly, one who touches mucous from his nose is surely considered someone who touches a normally covered part and must wash his hands.
Concerning learning Torah and reciting berachot: one who touched normally covered parts can b’dieved rub his hands on his clothes and subsequently learn or recite berachot, as clarified by the Shulchan Aruch 4:23 and Mishnah Berurah 4:61.