Some issues related to tayammum
* Many people can make tayammum from the same clean soil. When a person touches the soil, it is not regarded to have been used.
* More than one fard and supererogatory prayer can be performed with one tayammum. According to Imam Shafii, only one fard but more than one supererogatory prayer can be performed with one tayammum. It is recommended to make a new tayammum for each fard prayer to be free from controversy.
* If a person has wounds on half or more of his wudu organs, he makes tayammum.
* If a person is imprisoned or put into a cell where there is no water or clean soil, he delays his prayer and performs it later according to Imam Azam and Imam Muhammad. According to Abu Yusuf, he performs the prayer without reading anything. In other words, he imitates the prayer. He performs it again when he leaves the prison.
* If hajjis cannot find any water and if they have zamzam water that they are carrying as present, they make ghusl with zamzam. They cannot make tayammum.
* If a person has to make ghusl but finds water only enough for wudu, he makes tayammum. He does not have to use that water.
* Tayammum can be made before the time for a prayer starts but it is more appropriate to delay tayammum if the person hopes to find water before the recommended time for the prayer passes.
According to the other three madhhabs other than Hanafis, tayammum cannot be made before the time for a prayer starts.