Does placing water on the tissues violate the conditions for istijmar, and must the tissue be dry after urinating or defecating?

For the dry ablution (istinja) with a stone or similar object to be valid, it is a condition that the object used for wiping be dry, not wet. If one performs istijmar with something wet, the object wiped with becomes impure, and the impurity spreads. In such a case, it becomes necessary to use water to remove the impurity.