How do I remove the musty oder coming from my washing machine? It smells like mold and leaves the smell on my clothes, please help!!

I used to have the same problem in my old flat. We did a couple of hot empty cycles with extra fabric softener and that seemed to get rid of the worst of it. Although it did have a tendency to come back after a while. I have no idea where it ame form either as the washer was new.

I'll be interested to see what other people's solutions are- if anyone has a more permanent one.