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How to clean hats in the dishwasher? Short answer: sometimes — but only with the right hats, the proper setup, and careful preparation so you don’t ruin the brim, color, or fit.

People love the dishwasher trick because it’s fast and hands-off: load a few baseball caps on the top rack, run a gentle cycle, and hope for the best. But the reality is a little messier. Some hats survive and come out looking great; others shrink, fade, or lose their shape, especially vintage caps or hats with glued cardboard brims. This guide walks you through everything you need to know so you can decide whether your hat is a dishwasher candidate, and if so, exactly how to get safe, repeatable results.

What materials survive a dishwasher (and why)

Materials that generally do okay:

• Twill/cotton blend caps with plastic or stitched brims (modern sports caps).
• Polyester/performance fabric hats (often the most dishwasher-friendly).
• Mesh trucker hats with plastic brims.

Materials that are risky or must be hand-washed:

• Cardboard-stiffened brims (vintage caps) — water ruins the brim.
• Leather or suede trims — oven-like heat, detergent, and water will damage them.
• Wool or felt hats (beanies, fedora styles) — shape and shrinkage problems.
• Hats with glued embellishments or prints — hot water and detergent can loosen glue and fade prints.

Why: dishwashers use detergent and heated water that can saturate glued or cardboard materials, break adhesives, and stress stitching. Modern synthetic brims and machine-stitched components tolerate this environment much better. Several widely read guides and brand pages point out that you should check the construction before trusting a dishwasher.

Step 1: Inspect and prepare every hat before washing

Before you even consider loading hats into the dishwasher, take a few minutes to inspect and prep them properly:

Check the brim 

Flick it: does it sound hollow? Is it flexible? If the brim flexes or sounds hollow, it might contain cardboard — do not put it in the wash or dishwasher.

Look for glued parts or delicate embellishments 

Sewed patches are usually safer than glued patches.

Remove sweatbands or inserts

 If possible — some liners unzip or peel out for separate washing.

Spot-treat stains

Pre-treat visible sweat or grime with a slight squeeze of mild detergent or a stain stick. Let it sit for 10–15 minutes.

Choose the right detergent 

Use a mild, bleach-free dishwasher detergent. Bleach or strong citric detergents can fade colors. Several how-to guides recommend a gentle, bleach-free product.

Two methods: dishwasher method (step-by-step) and hand/spot-clean alternatives

Method A: The dishwasher method (step-by-step)

If your hat passes the inspection (no cardboard brim, no leather, no glue), follow this safe dishwasher routine:

Empty the dishwasher 

Start with a clean machine so hats don’t rub against dirty dishes.

Use the top rack only 

heat is gentler, and the top rack keeps hats away from heating elements. Place hats so they don’t flop or catch on tines.

Secure the hat 

Use a hat rack/frame or clip the hat lightly to the rack with clothespins or binder clips so the brim stays in shape. Some hat frames (plastic hat formers) are explicitly sold for dishwasher washing and help maintain their shape.

Use a gentle cycle 

The shortest, coolest wash available. Skip heated dry. Choose a low-temperature or “eco” cycle if possible.

Mild detergent only

 Use a small amount of a bleach-free detergent pod or powder. Avoid strong enzyme pods or bleach.

Run it alone 

Don’t mix hats with heavy pots or sharp items; a dedicated cycle reduces risk.

Immediate removal 

Take the hat out as soon as the cycle finishes; don’t leave it sitting in the hot, damp machine.

This approach is precisely what many mainstream guides recommend when they suggest dishwasher washing as an option for modern caps. It balances convenience with caution.

Method B: Hand wash and spot cleaning (when dishwasher is a no-go)

When the hat is delicate, vintage, wool, or leather-trimmed, hand washing is the safer path:

Fill a basin 

Do it with cool to lukewarm water and a tablespoon of mild detergent (or OxiClean for stubborn stains).

Gently submerge and agitate 

Use your hands and a soft brush on stained areas (sweatband, brim edge).

Rinse thoroughly 

Until the water runs clear.

For sweat stains, a paste of baking soda + water or an OxiClean soak can lift discoloration — soak 20–30 minutes, then hand scrub. Oxiclean’s official guidance for hats is a go-to for many caretakers of athletic caps.

Drying and reshaping: preserve the brim & fit

Drying is where many hats are accidentally ruined. Follow these tips:

• Never put hats in the dryer — heat will shrink and warp them.
• Use a form while drying: place hats on a clean bowl, a balled towel, or a hat form to hold shape. Some people use inflated balloons inside the crown to preserve shape while drying (an inexpensive hack).
• Air dry in shade — direct sunlight can fade fabric; shaded breezy spots are ideal.
• Check the brim shape after drying; reshape lightly by hand. If a brim warped, steam (from a kettle, carefully) can relax fibers for gentle reshaping — but only do this with synthetic brims, not cardboard.

These simple steps prevent most of the deformation problems people report after cleaning hats. The community-tested balloon and plate methods are standard in Reddit and DIY videos.

Deep cleaning & stubborn stains

For persistent yellow sweat stains or odors:

• Baking soda paste: Make a thick paste, rub into the sweatband or stained area, let sit for 30 minutes, then rinse.
• Vinegar soak: combine 1 part white vinegar with three parts water, soak 20–30 minutes to reduce odors.
• OxiClean soak: mix according to package directions and soak for 1–3 hours; rinse thoroughly. Oxiclean and other stain brands often show the best results for older sweat stains.

Always test a small hidden area first for colorfastness before using any chemical soak.

Common hat-washing gadgets and hacks people swear by

• Dishwasher hat frames — plastic framed inserts that keep brims rigid during the wash. (Several appliance and hat accessory sellers have these.)
• Balloon method — insert an inflated balloon to hold the crown shape while washing/drying. Reddit users frequently recommend this inexpensive hack.
• Utilize clothespins or binder clips to secure the hat to the top rack to prevent flapping.
• Hat cages or forms — for collectors, a rigid plastic hat form is best to maintain value.

These little helpers can be the difference between a hat that returns to your head looking fresh and one that looks oddly warped.

Problems & fixes: what to do when things go wrong

• Warped brim — gently steam and reshape, or place the hat on a bowl and press it back into form as it dries—only steam synthetic brims.
• Color bleeding or fading — avoid bleach and harsh pods; use cold cycles or hand wash. If fading happens, dyeing may be an option for some fabrics, but it’s not a great fix for printed logos.
• Cardboard brim collapse — untreated, this is usually permanent. For collectible/vintage hats, consult a hat restoration professional before washing.
• Shrinkage — too much heat causes shrinkage; avoid hot cycles and never tumble dry.

Many online threads (and appliance help blogs) emphasize that the most common irreversible mistake is washing hats with cardboard brims — that one test (flick the brim) is worth doing every time.

Related: Can You Put Owala in the Dishwasher Safely

Conclusion

How to clean hats in the dishwasher boils down to three choices: check construction, choose a gentle dishwasher top-rack method for modern caps, or hand-wash delicate or vintage pieces. When you follow the preparation, secure placement, mild detergent, and careful drying steps outlined above, the dishwasher can be a fast way to refresh standard baseball caps — but it’s not a universal fix. Treat each hat as an individual, and when in doubt, hand wash. That’s the safest route to keep shape, color, and value intact.

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