We had a leak in the roof a while ago that caused water stains on the wall. The leak should be fixed now, but we wanted to wait a bit before painting the wall until we are sure that there is no more water leaking in. I feel that it is now really hard to tell if the wall is wet where the old stain is, or just cold.
What is the best way to tell if the drywall is actually moist or if it is dry. Preferably without buying any moisture meter or so.