It creeps up on you. First it is just the towels, then the gym kit, then a shirt you have worn for twenty minutes that already smells vaguely of a cellar. You sniff the laundry basket, blame the detergent, buy a different detergent, and nothing changes — because the thing that needs washing is the washing machine.
This is one of those household jobs that sounds intimidating and takes about half an hour of mostly unattended time. Do it properly once and then keep on top of it, and you will stop rewashing loads, which is the hidden cost of a neglected drum.
Why machines start to smell in the first place
Modern laundry habits are gentle: cool water, liquid detergent, a door kept shut between washes. All three are good for fabric and energy bills, and all three suit the bacteria and mould that live on the film of detergent, fabric softener and body oils coating the inside of the machine. Cool water does not dissolve that residue fully, so it builds into a soft grey layer where moisture never quite leaves.
That layer is what you are removing. It is not usually in the part of the drum you can see — it hides in the rubber door seal, the detergent drawer, the filter and the hidden outer tub. So a single hot cycle on its own rarely fixes anything.
