The washing machine drum is in contact with every item of laundry you wash, every wash cycle, year after year. Despite being stainless steel — a material that resists corrosion and is non-porous — the drum surface accumulates a combination of detergent film, fabric softener residue, mineral scale from hard water, and bio-organic deposits from soil and body residue on laundry. Left to build up, this film contributes to odours, can transfer a grey or dull tinge to light fabrics, and in severe cases allows bacterial colonies to establish on the drum surface itself.
What Accumulates in the Drum
Detergent film: Undissolved detergent — particularly powder detergent used at low temperatures — leaves a chalky residue on drum surfaces and in the drum perforations.
Fabric softener: Liquid fabric softener leaves a waxy, greasy film that is resistant to hot water alone. Over time this film becomes sticky, attracting lint and debris.
Limescale: Hard water deposits calcium and magnesium compounds on every surface the water touches, including the drum. Scale appears as a white or grey film and can reduce the effectiveness of heating elements (which sit inside the drum water path).
Bio-film: Low-temperature washing cycles — common on modern machines for energy efficiency — do not kill bacteria. Organic residue from laundry feeds bacterial colonies that establish on the drum walls, producing the characteristic sour odour.
Drum Cleaning Methods
Method 1 — Hot Cycle with Cleaning Agent
The primary drum cleaning method is a hot wash cycle with a dedicated cleaning agent or white vinegar as described in the cleaning cycle article. This handles bio-film, detergent residue, and light limescale.
Method 2 — Manual Wipe-Down
After a hot cleaning cycle, manually wipe the drum interior while it is still warm. Use a microfibre cloth dampened with a diluted citric acid solution (1 teaspoon citric acid powder in 500 ml water). Work methodically around the drum, paying attention to:
- The lifter paddles (the raised fins inside the drum) — residue accumulates along their edges and in the gap where they meet the drum wall
- The drum perforations — use a soft brush to dislodge debris from inside the holes
- The area around the back drum wall
Method 3 — Descaling Treatment
For drums with visible limescale coating — a rough, chalky texture to the touch — use a dedicated appliance descaler product or a concentrated citric acid solution. Follow product instructions, which typically involve soaking or a dedicated descale cycle.
Warning: Steel Wool and Abrasives
Never use steel wool, abrasive pads, or harsh chemical solvents inside the drum. Scratching the stainless steel surface creates microscopic channels where scale and bacteria establish more aggressively than on an intact surface.
Frequency
Clean the drum once a month as part of your regular cleaning cycle maintenance. Manual wipe-downs can be done as needed when visible residue is present. Descaling treatments are warranted every 3–6 months in hard water areas.