What is the ruling on praying in clothes that have been defiled by an impurity whose exact location is unknown?

If the hand is dry and has impurity on it, the impurity does not transfer from it to the clothes. The same applies if you doubt its dryness. However, if you are certain that the hand was defiled with urine and had not dried, then if it touched the clothes, they become impure, and the touched area must be washed. Prayer is not valid without purifying the area, according to the majority of scholars, while some scholars permit overlooking such a minor impurity.