What is the ruling on wetness or moisture that affects the bottom of shoes and seeps into socks, as a result of water used for istinja in public restrooms, or rainwater in the streets and the dirt it contains? Is that water considered najis (impure), and is it obligatory to wash the inside of the shoe upon feeling wetness? Is prayer valid with such socks?

The basic principle regarding the floor of a bathroom and what is on it, such as water and sandals, as well as the ground of streets and what is on them, such as water and mud, is purity. Nothing from these is ruled ritually impure except with certainty. Based on this, sandals or socks do not become impure from what has been mentioned, and there is no need to change or purify them. It is obligatory to shut the door to obsessive doubts and not to give in to them.