Is it permissible to perform Tayammum on a single limb, such as the nose, and what is the detailed method for doing so?

In wudu and ghusl, sniffing water into the nose (istishaq) is recommended, not obligatory, according to the preponderant opinion. So, if someone omits it, whether able or unable, their wudu is valid and they are not required to perform tayammum. However, according to the view that istishaq is obligatory, one must wash what is possible and perform tayammum for what cannot be washed, while observing the sequence and continuity for minor ritual impurity according to the Hanbalis. It is permissible to perform tayammum before washing the face to avoid dispute. The method of tayammum for a limb that cannot be washed is the usual tayammum: striking the pure earth and wiping the face and hands.