Question 172: Is offering Salaah (Prayer) after having performed Istijmaar (cleansing the private parts with a hard material after urination or defecation) valid? Is it permissible to perform Istijmaar in the absence of water? If water later becomes available, should I make Istinjaa’ (cleansing the private parts with water after urination or defecation)?
Answer: If Istijmaar is made thrice using a pure solid object, with the exception of bones or dung, it is permissible to perform Salaah, and one need not perform Istinjaa’ even if water becomes available. This was done by the Prophet (peace be upon him) and is according to the Ijmaa` (consensus of scholars) held on this point… read more here.