Is it valid to clean oneself (istinja') using dry paper tissues, and then several times with wet ones until clean, despite the availability of water?

Using tissues for istinja' (cleansing after relieving oneself) is valid and sufficient. However, it is better to combine tissues with water, as combining them removes both the substance and its trace. This is because Allah praised the people of Quba for combining them. If one wishes to rely on only one of them, water is superior.