Last Updated on September 22, 2026 by Umar Farooq
Flick the brim with a finger before you do anything else. If it sounds hollow, the stiffener inside is cardboard and the hat can only ever be spot cleaned. If it sounds solid, the brim is plastic and the hat can go in a mesh bag on a cold gentle cycle with a small load of laundry. Either way it dries on a round form, never in a dryer.
That one flick is the whole decision, and it takes two seconds. Everything below assumes you have done it.
The brim test, and the year that explains it
A baseball cap is a fabric shell wrapped around a stiffener, and the stiffener is the part that cannot be replaced. Modern caps use plastic. Older ones use cardboard, which turns to pulp the moment it is submerged and never comes back — the brim ends up wavy, soft and permanently misshapen.
Nike gives the test in one line: “Quickly check by flicking the bill of the hat with your finger. If the insert is made of cardboard, it will sound a bit hollow when it’s tapped or flicked” (how to wash a baseball cap).
Maytag adds the detail that turns this from a tip into a rule — an actual date. “Some hats, especially older ones made prior to 1983, have a cardboard bill that will get ruined in the washer” (how to wash a baseball cap, snapback or dad hat). So a vintage cap, a inherited cap, or anything you suspect is old enough to matter gets the flick test and then gets spot cleaned only.
Two other disqualifiers from the same Maytag page: no care label means hand wash — “your best bet is hand washing to prevent any fading or structural damage to the brim” — and “don’t machine wash any hat that already has rips or holes, as the washer motion can make them worse.”
How to wash a hat in the machine, step by step
Only for a plastic brim, an intact hat and a care label that allows it.
- Pretreat the sweatband with a non-bleach stain remover. That band is where the discolouration actually is, and a general wash will not touch it.
- Put the hat in a mesh bag or a knotted pillowcase. Maytag’s reason is blunt — it protects the cap “from potential damage from the washer agitation.”
- Add a small load of laundry with it. This is the instruction people skip, and Maytag gives the mechanism: it “helps prevent matting and misshaping.” A cap alone in a drum gets thrown against the wall on every rotation with nothing to cushion it. Towels or T-shirts, nothing heavy, nothing with zips.
- Cold water, gentle cycle, slow spin. Maytag specifies “a gentle cycle with slow spin speeds, cool water and a mild detergent.” Cotton caps can shrink, and the shrinking comes from heat.
- Out of the machine and onto a form immediately. Do not leave it sitting damp in the drum.
The same logic — small rigid item, mesh bag, companion load — is why washing shoes in a washing machine works the way it does. And if the care label is a set of symbols rather than words, they are decoded in laundry symbols.
Hand washing is still the method to beat
Every source here, including both appliance makers, says hand washing is safer. Maytag: it “is the safest and most recommended hat washing method.”
Fill a sink with cool water and about a tablespoon of mild detergent. Work any marks with an old toothbrush — the sweatband and the front panel are where the dirt is. Let it soak about an hour, checking the stained areas as you go. Rinse until the water runs clear, press it in a towel rather than wringing it, and reshape.
Cool water, not warm, if the colours are strong. A dark cap with a white logo is the classic bleed risk, and the damage is done in the first minute. The general technique carries over from how to hand wash clothes.
The dishwasher: the hat maker says yes, the appliance maker says no
This is the method the internet loves, and the two best sources on this page flatly disagree about it.
Nike endorses it. Top rack, and it is “better to wash multiple baseball caps” at once — with the caveat to “try to use a dishwasher detergent that doesn’t have bleach or harsh chemicals.”
Maytag rejects it. “It’s possible to wash a hat in the dishwasher, but not recommended due to high heat and bleach-based dish detergents. To keep your hat in tip-top shape, stick to the gentler methods outlined above.”
Notice who is saying what. The appliance manufacturer — the one that would benefit from you using the appliance — is the one telling you not to. That is worth weighting, and the reasoning is concrete rather than cautious: a dishwasher’s drying cycle runs far hotter than any laundry setting, and most dish detergents contain bleaching agents that a cap’s colours were never tested against.
If you do it anyway: top rack only, no heated dry, and a detergent you have checked for bleach. This site would use the sink.
Drying is where the shape is lost
Never the dryer. Maytag: “the high heat and tumbling can damage your hat”, and Nike adds that dryers “can get too hot and cause the hat to lose its shape and possibly even shrink.”
Dry it on something round and roughly head-sized. A purpose-made hat form is ideal; an upside-down bowl, a coffee tin or a balled-up towel pushed inside the crown all work. The point is that the cap dries in the shape you want rather than collapsing into the shape gravity gives it.
Out of direct sun, and give it longer than you think — the seams and the sweatband hold water after the shell feels dry.
FAQ
Can you put a hat in the washing machine?
If the brim is plastic, the hat is undamaged and the label allows it, yes — in a mesh bag on a cold gentle cycle with a small load. A cardboard brim never goes in.
How do you tell if a hat brim is cardboard?
Flick it with a finger. A hollow sound means cardboard. Caps made before 1983 are especially likely to have one.
Can you wash a hat in the dishwasher?
Nike says yes on the top rack with a bleach-free detergent. Maytag says no, because of the high heat and bleach in dish detergents. The appliance maker’s caution is the one to follow.
How do you keep a hat from losing its shape?
Dry it on a hat form or something round the size of a head, and never in a dryer. The shape is set as it dries.
How do you clean the sweatband on a cap?
Pretreat it directly with a non-bleach stain remover and work it with a soft brush before the hat goes in water. A general wash will not lift it on its own.
Can you wash a hat with cardboard in the brim?
Not by soaking or machine washing. Spot clean the fabric only, keeping the brim as dry as you can manage.
Two seconds of testing saves the hat
Flick the brim, use a bag, add some company to the load, and dry it on something round. Hats are easy to clean and easy to ruin, and almost every ruined one was either soaked with a cardboard bill inside or left to dry flat on a radiator.
