The bleach and soda washes suggestions work fine, I've done a quick wash through with a small amount of bleach. However I found the rubber around the washer door has black marks inside the rim so I've just bought some Dr Beckmann Service-it Washing machine cleaner from Asda (nearly £3 though). Its a one treatment bottle where you wipe around the rubber to clean off any gunge, then soak the detergent drawer in a small diluted amount, and finally pour the rest into the detergent drawer and empty washer wash at 60 degrees. Supposed to freshen clean and maintain the washer. Haven't used it yet but I intend to do it this week. I'm blaming the new Surf liquid detergent and conditioner stuff for the gunge.