How can an apartment be purified after it has been completely defiled by semen and urine from a person who lived there for a year or more, especially the furniture and upholstery that cannot be washed with abundant water, and is it obligatory to inform the tenant or buyer about this impurity?

One who masturbates must repent to Allah, as it is forbidden. Not cleansing oneself from urine is a grievous sin that leads its perpetrator to Hell, as the Prophet, peace and blessings be upon him, said: "As for one of them, he used not to screen himself from urine." As long as the furniture remains impure, its owner must inform anyone who wishes to rent or buy it about its impurity, or purify it beforehand. This falls under the category of enjoining what is right and forbidding what is wrong.