There is a specific disappointment in pulling a warm towel out of the drum, burying your face in it, and getting a whiff of something stagnant underneath the fabric conditioner. You washed it. It is technically clean. It smells like the inside of a water butt. For years I blamed the towels, then the detergent, then the weather, before accepting the obvious: the machine itself needed washing.
Modern laundry habits almost guarantee this. We wash cool to save energy, we use liquid detergent, we close the door the second the load is out, and the result is a warm, damp, soapy interior that bacteria and mould find extremely comfortable. The grey-brown film that builds up inside the drum, the pipes and the seal isn't dirt in the normal sense. It's a layer of residue, and it is the smell.
Start with the drawer, because it's the worst bit
Pull the detergent drawer right out. On most machines there's a small release catch or you simply pull firmly past the stop. What you find underneath is usually a slimy mix of undissolved detergent and softener, sometimes with a pink or black bloom on it.
Wash the drawer in hot water with a little washing-up liquid and an old toothbrush, paying attention to the softener compartment and the little siphon cap, which comes out on most models. Then clean the cavity the drawer slides into, because residue clings to the roof of it where you can't see. A damp cloth wrapped around a long-handled brush does the job. Let both dry before you put it back.
