Based on the context and the answer, generate a question. 

Context: I could n't think for the life of me what this stuff could be . But I started grabbing clothes and shaking them outside to rid them of as much mystery substance as possible . I was still wracking my brain when , as I shook out another handful of clothes , a diaper flew out .

Answer:

Because a diaper somehow got into the laundry to be washed .



What may be the reason why a diaper would be in with clothes ?