بسم الله الرحمن الرحيم
(1) If you want to wash it with other pure clothes then first you should clean the impure clothes then wash them together. But if you mix them without cleaning then you should wash them in washing machine thrice. if you put the clothes in the part of machine which dries and squeeze them thrice with three waters, they will become pure and clean.
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.