Do clothes become impure by touching a bed that has impure wetness, if the bed is not a place for prayer?

What was mentioned is correct. Scholars have differed on the ruling concerning a wet garment touching a dry, impure spot. The Shafi'is and Hanbalis hold that the wet garment becomes impure if it touches something dry and impure. In contrast, the Hanafis and Malikis believe it does not become impure by doing so. The more cautious opinion is the first one: to purify the wet garment if it touches a dry, impure mattress.