What is wrong with my washing machine???

Question

My family is renting a house with a use washing machine and dryer. Anyways, I like always wash my clothes in cold water and usually wash them with soap but recently switched to powdered soap. So today I thought I'd get my clothes extra clean using the hot water button which I never use. When my clothes got done washing there were small crumbley hard black stuff on my clothes. What is this, it has never happened?

Answer 1

run the washing machine without any clothes , its dirty nothing to do with the temp, just back up gunk from all the washes