Causes of grease, slime and black mould inside washing machines
This article looks at the importance of a maintenance wash using the hottest program, and how to get rid of mouldy, musty or bad smells from washing machines. It also points to the causes so as to protect from the problem in the first place or prevent re-occurrence. A washing machine covered with gunge and grease inside can also cause marks on laundry especially if laundry gets dragged round the rim of the drum and picks up grease from under the door seal.
There are various products available online and in supermarkets claiming to freshen up washing machines and get rid of bad odours. My personal experience with these products (which are also aimed at dishwashers) is that they do a good job of freshening up a relatively clean washer or dishwasher but are not so good at curing a genuinely smelly one if the problem has been allowed to get really bad. If your appliance is seriously smelly, especially if coated in black mould or greasy gunge, then it can be very difficult or even impossible to cure, but there are some things worth trying..
Carry out one or more maintenance washesNot many people use hot washes any more, and this is partly to blame for the bad smells because hot water helps to kill bacteria and cut down grease. One of the first things to try is to put the washing machine on a boil wash cycle (90° or 95°) with detergent inside – but no laundry. You may need to try this more than once, but badly affected washing machines caked in bacteria and gunge may be beyond help if left too late.
Also, you could try to clean the washing machine inside using soda crystals which dissolve grease. I recommend putting half a packet inside the drum and washing on a boil wash (or follow instructions on the packet). Using this method every month or so, or using ordinary detergent if no soda crystals are available can help prevent smells from your washing machine. If your washing machine is badly affected by grease and slime, it may be very difficult to remove it.
This is particularly important if you mostly use low temperature washes and (or) liquid detergent, and other washing machine detergent which doesn’t contain bleaching agents such as colour friendly detergent. If you do, then buy some detergent that does, and use it for your maintenance washes. This will help kill off bacteria and prevent black mould and grease. Tip: Look for something like, "bleaching agents" in the ingredients. Some manufacturers recommend using biological detergent for the maintenance wash. I’m not sure exactly why because biological detergent only really works at low temperatures and the biological enzymes get killed off at high temperatures. It might be worth trying both biological and non biological detergent. The main criteria is – no laundry and very hot wash cycle.
Don’t put chemical cleaning bleach in the washing machine, there are certain types of bleach (eg. oxygen bleach) that are appropriate for laundry.
Get rid of washing machine odours using vinegar
White distilled vinegar has an array of uses. Try putting half a cup of white (distilled) vinegar inside an empty machine and put it on a boil wash. Note that because the first bit of water goes into the sump hose and is sealed off, I recommend that you wait until the washing machine has been filling for about 15 seconds before pouring the vinegar into the soap drawer where water is running in to let it wash down into the machine. I've had reports back from people that this does actually work.
(This is a completely revised and updated article first published in 2002 on my other site Washerhelp )
What causes washing machine smells?
Washing machines now commonly suffer from a build up of a greasy deposit and bacteria which causes bad smells, rots hoses & door seals and blocks the pressure system causing overfilling or spin failure. An even more serious consequence of this problem is that the aluminium based drum spiders can be corroded by the build up of grease and gunge, which can cause one or more of the drum’s arms to break. This is often fatal to the washing machine.
This problem was virtually unheard of before the 1980s but when detergents started to become more environmentally "friendly" and liquid detergents were invented this issue suddenly appeared. It seems that the problem is worse when a combination of factors are involved, but almost everyone suffering the worst cases of this slimy grease uses 40 degrees washes almost exclusively. This, combined with either poor quality detergents, not using the recommended quantities, or only using colour-friendly detergents or liquid detergent which contain no bleach allowing bacteria to thrive can seriously rot a washing machine inside.
Here’s an example of the level of gunge that can build up inside a washing machine.
Large deposits of grease, slime and undissolved detergent have built up on the underside of this door seal, which can cause smells. If you were to wash greasy plates in a plastic washing up bowl with the water at 40 degrees you would expect the plates to come clean but when emptying the bowl there is likely to be a greasy film coating it. To break down grease you need higher temperatures. Washing the same plates at 60 degrees or higher I would expect the grease to be dissolved more effectively.
To check if your washing machine is being badly affected, carefully examine the inside of the door seal for slime and grease. Pull the lip back in front of the drum and look underneath and on the lip of the tub. If the door seal is covered in black mould it will probably need replacing.
Smells from the plumbing
Washing machine smells can also be caused by plumbing issues. Check out this article for more details – Smells caused by plumbing faults.
Low temperature washes are part of the smelly washing machine problem Washing at 30 degrees?