Forgot Laundry in the Washer Overnight? Rewash or Not?

You can tell musty laundry by its smell: open the door (or the lid) and leave it open. Look first: if you see a film, fuzz (mold) or black spots, don't shake anything out. Otherwise take a thick item from the middle, such as a towel, unfold it and sniff it. Here's how to decide:

• Smells fresh, just wrinkled: Hang it up or, if the label allows it, put it in the dryer. Wet shirts wrinkle, so hang each one on its own hanger. You don't need a second wash cycle.
• Smells musty or sour: Wash it again (see the temperature below) and don't dry it beforehand.
• You see fuzz, a film or black spots: Wash it again. There's no promise that everything comes out. If you have allergies, asthma or a weakened immune system, have someone else unload the laundry if possible, and get medical advice if you have symptoms.
• Light items picked up dye: Don't hang them up and don't dry them. Wash these items quickly and on their own; there's no promise that all the color comes out.

Don't dry musty laundry in the hope that the smell will go away. A consumer magazine warns that the dryer can lock the smell in. Also, don't leave the dryer running unattended and clean the lint filter regularly. If you don't have a dryer, hang the items one by one with space between them on a drying rack, ideally in fresh air where that's allowed (check your lease or HOA rules).

How long wet laundry can stay in the washer can't be said exactly: after a night there's often a smell already, while visible mold usually comes later. Guides give rough benchmarks, not measurements:

• Up to about 2 hours is usually considered fine.
• One night (8–12 hours): the laundry often smells musty already, but sometimes it's fine, especially with the door open. The sniff test decides.
• A day, two days or the whole weekend: a smell is likely, and in a closed, damp machine mold can form after one or two days.

Laundry gets musty because moisture, warmth and detergent residue give bacteria a good breeding ground. It happens faster with a stuffed drum, sweaty workout clothes or worn shirts. Take the numbers as a guide, not a free pass.

Wash musty laundry again at 60 °C (140 °F) if it's sturdy cotton, such as towels, bedding and white T-shirts, but no hotter than the care label allows. The care label is the small tag sewn into the collar or the side seam. On labels that follow the European care system, the number in the washtub symbol is a maximum, not a recommendation. US care labels usually give words, often with symbols: cold is up to 86 °F (30 °C), warm up to 111 °F (44 °C) and hot up to 145 °F (63 °C). On a US care label, 140 °F counts as “hot”. If the label shows dots or words like “warm” instead of a number, choose one step cooler. If the label is missing, start with a cool, gentle wash and repeat the cycle if a smell remains, rather than washing hot.

• Detergent: A detergent with oxygen bleach (non-chlorine bleach), usually a heavy-duty powder. The package often says heavy-duty or lists oxygen bleach, not “color”. The bleach is not chlorine bleach and clearly reduces the bacteria in the machine; mold is more stubborn. Only for whites and sturdy, colorfast cotton. If you have sensitive skin, read the package; if your skin gets irritated, get medical advice.
• Program: Choose the cycle that matches the temperature on the label, such as the cotton cycle, never a quick cycle. If the cycles on your washer have different names, or your washer only offers cold, warm and hot, choose the setting that matches the label; for the 60 °C (140 °F) rewash that is hot. On some machines, the eco cycle doesn't reach the temperature shown.
• Load size: With wet laundry, fill the drum only halfway, as the GINETEX care guidance (the European care label system) says. If it doesn't all fit, wash in two loads.
• Dosage: Follow the package for your amount of laundry. More detergent doesn't help; residue feeds germs.

You don't need 90–95 °C (194–203 °F): in Germany, the Federal Institute for Risk Assessment and the Federal Environment Agency consider washing laundry at near-boiling temperatures at home generally unnecessary. Mild detergents without oxygen bleach hardly lower the germ count, though. The rewash with powder is a special case; afterward you go back to washing by the label.

If the label forbids heat or bleach:

• Colored items at 40 °C (104 °F) or a crossed-out triangle (“do not bleach”): the highest allowed temperature, color or delicate detergent, repeat if a smell remains.
• Only liquid detergent on hand: do the same, wash at the highest temperature the label allows and repeat if a smell remains. A bit of smell may stay.
• Triangle with lines: only oxygen bleach (non-chlorine bleach) is allowed.

It gets dangerous when products are mixed. You don't need vinegar for the rewash: a German consumer group advises against it because it can damage seals, and also advises against hygiene rinses (laundry sanitizers). With 60 °C (140 °F) and powder you can do without both.

Wool: Don't rewash musty wool hot, it felts (shrinks and mats) easily. If the label says hand wash, stick with that. Otherwise use the wool cycle with a mild wool detergent and fill the drum only to a third. If your washer has no wool cycle, hand wash at up to about 30 °C (86 °F). Dry wool flat (lay flat to dry). Whether a rewash reliably removes the musty smell is not proven, so repeat it gently rather than hot. If the wool is just wet and doesn't smell, press the water out without wringing.

Silk and delicates: Here too the label counts. Choose a gentle cycle with a mild detergent for delicates and a low spin speed. If the label shows a hand in the washtub, only hand washing is allowed. If the washtub is crossed out, the item doesn't go into water: air it out in a well-ventilated spot. If that doesn't help and the label allows dry cleaning (circle without a cross), take it to the dry cleaner.

Workout clothes: They're often labeled 30 or 40 °C (86 or 104 °F), so the 60 °C (140 °F) recipe from above doesn't apply here. Wash as warm as the label allows and repeat the cycle if a smell remains. Don't leave sweaty clothes damp in a gym bag after your workout.

Towels and bedding: They hold a lot of moisture and start to smell fast, but they're the easiest case: white or colorfast items whose label allows 60 °C (140 °F) and heavy-duty powder detergent get washed at 60 °C (140 °F). Don't overload the drum, then dry them quickly and completely. Colored or printed items get color detergent at the highest allowed temperature.

Work clothes: With blended fabrics and reflective stripes, the label counts. For protective and high-visibility clothing, only the manufacturer's care instructions apply. Textiles soaked with oil or grease don't belong in the dryer, they can ignite on their own, and after washing don't fold or stack them while hot.

After forgetting laundry, you only clean the washer if it smells: leave the door (or the lid, on a top loader) and the detergent drawer open until everything is dry, and wipe the rubber seal and the drawer dry. If the smell comes from the machine, run an empty cycle at 60 °C (140 °F) with heavy-duty powder detergent, unless your washer's manual says otherwise. As prevention, one such cycle about once a month is enough. If the washer isn't yours, for example in a shared laundry room or a laundromat, don't run an empty cycle; tell the building manager or the operator instead. If laundry smells musty even after a completely normal wash cycle, the cause is somewhere else, for example in the machine itself.

Forgetting is normal, especially when the evening was long or the laundry room is two floors down. A few habits make it happen less often:

• Set an alarm for the end of the cycle, even if you have a fixed slot in the laundry room.
• If you use delay start, set it so the cycle ends shortly before you get up, not at midnight.
• With rinse hold, the laundry stays in the rinse water. Finish the cycle afterward: drain and spin, don't just open the door.
• Put the laundry basket next to the washer and unload first thing when you get up. If you share the washer, agree beforehand who unloads.