It is a bit of a major job and I would first try running machine with a cleaner. You can buy packets of washing machine or dishwasher descaler. Put water level on full, choose a warm or hot wash and pour the packet of descaler in to the bowl. Allow it to agitate for 5 minutes then pause and let it soak for an hour then continue the wash cycle. See if that makes any difference. Some people even say white vinegar is good for removing build up as well. Never tried it myself but you could add some to the water if you have some.
Lincoln Appliance NZ, November 2014
