Islam calls for cleanliness and tidiness; in fact, cleanliness is godliness, as they say. Thus, we see that Muslims are encouraged by the Sunnah to cut their nails and comb their heir, not to be dishevelled.
Dr. Rif`at Fawzi, professor of Shari`ah at Cairo Univ., states: “Being in a state of Janabah (after having sexual intercourse with wife or after having a wet dream) does not bar you from observing all permissible acts with the exception of certain acts such as reading the Qur’an and sitting in the mosque; and therefore you can cut your nails or hair. There is nothing wrong in doing so.”
Sheikh Sayyed Sabiq states: “It is acceptable for a person in post-sex impurity or a menstruating woman to remove their hairs, cut their nails, go to the markets, and so on, there is no problem in that. `Ata said that such people can get cupped, cut their nails and their hair, and that this is allowed even if he/she has not performed the regular ablution. (Related by al-Bukhari)”