my washer smells musty, especially right after a cycle finishes. how do i clean it?

Diagnosis

This musty odor is caused by the accumulation of "scrud"—a waxy buildup of undissolved detergent, fabric softener, and organic skin cells—which traps moisture and creates a breeding ground for mildew and mold. In the Samsung WA55CG7100AW, this typically occurs in the stagnant water pockets of the detergent dispenser housing and the gap between the inner stainless steel drum and the outer plastic tub. Because this model uses a high-efficiency (HE) impeller system, it uses less water, which often fails to flush out all the residue from the top of the drum. The smell is most prominent after a cycle because the humidity is at its peak, and the agitation process has loosened the biofilm attached to the outer tub, releasing volatile organic compounds (VOCs) into the air. You can confirm this by wiping a damp white paper towel along the underside of the detergent drawer rim; if the towel comes away with grey or black slime, you have a systemic biofilm issue that a standard wash cannot resolve.

How to Fix It

To fully sanitize the WA55CG7100AW and eliminate the odor, follow this deep-cleaning sequence:

1. Clear the Dispenser: Press the release tab on the detergent drawer and pull it completely out of the machine. Use a toothbrush and a mixture of warm water and white vinegar to scrub the drawer itself and the ceiling of the dispenser cavity where mold typically clings.
2. Prepare the Cleaning Agent: Do not use laundry detergent. Instead, use a dedicated washing machine cleaner like Affresh or OxiClean WasherCleaner. If using bleach, pour 1 cup of liquid chlorine bleach directly into the bleach dispenser compartment; do not pour it directly onto the drum to avoid pitting the stainless steel.
3. Execute the Tub Clean Cycle: Press the Power button, then select the "Tub Clean" cycle. Ensure the water temperature is set to "Hot." This specific cycle is programmed to use a higher water level and a longer soak time than a standard wash to penetrate the outer tub.
4. Post-Cycle Wipe Down: Once the cycle completes, use a microfiber cloth to wipe the top rim of the tub and the rubber seals around the agitator/impeller area.
5. Ventilation: Prop the lid open at a 45-degree angle for at least 4 hours to allow the internal humidity to evaporate completely.

If That Didn't Work

• Deep Clean the Dispenser Housing: If the smell persists, remove the detergent drawer again and use a pipe cleaner or a flexible brush to scrub the water inlet nozzles at the back of the dispenser housing. These often collect black mold that the Tub Clean cycle cannot reach.
• Vinegar Shock Treatment: Run a second Tub Clean cycle, but this time use 2 cups of distilled white vinegar poured directly into the drum. The acidity of the vinegar breaks down the alkaline detergent buildup (scrud) that bleach sometimes cannot penetrate.
• Inspect the Drain Hose: Check the installation of the drain hose at the back of the machine. If the hose is pushed too far down into the standpipe (creating a siphon) or if there is a "U" trap with standing water, sewer gases or stagnant water can back up into the tub. Ensure there is an air gap between the hose and the standpipe.
• Manual Scrubbing: Use a nylon brush to scrub the top 2 inches of the stainless steel drum just below the rim, as this area often remains dry during cycles and accumulates a ring of grime.

Heads Up

• Avoid Fabric Softeners: Liquid fabric softeners are the primary cause of biofilm buildup in Samsung washers. Switch to distilled white vinegar in the softener compartment to keep the tub cleaner.
• Use HE Detergent Only: Only use High-Efficiency (HE) detergents. Standard detergents create excessive suds that cling to the outer tub and trap odors.
• Monthly Maintenance: Schedule a "Tub Clean" cycle every 30 wash cycles or once a month to prevent the return of the musty smell.
• Lid Discipline: Never close the lid immediately after a load. Keep the lid open until the drum is bone-dry to the touch.