What should a person do if they experience a wet dream, or discharge of madhiy (pre-seminal fluid) or light urine during sleep, without knowing the position of their hand?

If one is certain that a part of his body has been afflicted by impurity (najasa), he must purify that area. However, if there is doubt, nothing is required, because the default state is purity. One should wash their hands three times after waking up before putting them into a vessel, because the Prophet (peace be upon him) said: "For he does not know where his hand spent the night."