The thing with cleaning your washing machine is that no matter how good the washing machine cleaner you're using, sometimes it's just best to give your machine a good-old manual scrub. This particularly applies to the tray and tray compartment area, the door, and the rubber seal.
Cleaning these parts of your washing is crucial to keeping your washing machine hygienic. When you read horror stories about washing machines accumulating enough bacteria to potentially make you sick, they're not really talking about the metal drum (although it can, of course, also become unhygienic over time if you don't do hot washes). It's actually the plastic and rubber parts that tend to collect bacteria.
The inside of the door is also a potentially unhygienic area – if, like we do, you leave your washing machine door open to air out the inside, then it will collect dust and bacteria, especially if your washing machine is anywhere near your kitchen worktops. In hard water areas, bacteria and dust will settle on top of detergent residue, making the problem worse.
Which is why every month or so, we take our collection of scrubby cloths to our washing machines. We've tried all sorts of things, and microfibre cloths win hands down, every time. The word 'micro' is key here: the small fibres physically pick up dirt and bacteria rather than just moving them around. E-cloth started the whole microfibre cleaning thing, and we still regularly use a classic e-cloth to thoroughly scrub the door, inside the rubber seal, and the tray.
Never use a kitchen sponge for cleaning your washing machine: all you'll get is a load of foam with the bacteria and grime suspended inside it – very difficult to completely remove that foam from your machine.
And what about the old toothbrush trick for cleaning the tray? Maybe we're becoming germ-phobic, but if you use it more than a couple of times, then you will have bacteria on that toothbrush. We've started using a silicone bottle brush to reach those washing machine tray corners instead.