Baseball cap secured inside household dishwasher

Keep Your Cap Shape: 10 Step Dishwasher Method for NZ Hats

A dishwasher works for some hats and ruins others. Colourfast cotton or polyester caps with no structure can sometimes handle a gentle, cool cycle. Wool, leather, felt, straw, and anything with a shaped or stiffened brim should stay out entirely. Always check the care label first, use the top rack only, run the machine empty, and skip the heated dry.

TL;DR:

  • Only unstructured, colorfast cotton or polyester caps without stiff brims or stiffened panels are suitable for dishwasher cleaning; structured or delicate hats are not.
  • Use a cool or eco cycle on the top rack without detergent or with a neutral, mild detergent, and remove the hat immediately after the cycle ends to prevent warping.
  • Avoid dishwasher drying, heated cycles, and any detergents containing bleach or chlorinated agents, as they can cause shrinkage and damage to fabrics and materials.
  • Always reshape hats while damp, support the brim during air-drying, and keep hats out of direct heat or sunlight to preserve shape and color.
  • Hand washing remains the safest option for most hats, especially wool, leather, and straw, with gentle soaking and air-drying being the recommended process.
Urbancaps
Find Headwear Built for Everyday Wear
Explore premium caps and hats designed for durable, stylish wear across Kiwi lifestyles, outdoor activities, and everyday outfits.
Shop premium headwear

Table of Contents

When it’s safe to use a dishwasher

A dishwasher can work for simple, unstructured caps made from colourfast cotton or polyester, the kind with no cardboard inserts, no buckram stiffening, and no leather trim. These fabrics are sturdy enough to survive water movement and a mild detergent without losing shape or colour. Anything built to hold a brim or crown shape is a different story.

Certain materials and constructions should never go anywhere near a dishwasher:

  • Wool hats and knitted beanies, which shrink and felt when exposed to heat and agitation.
  • Leather hats and trims, which crack, stiffen, or lose their finish when wet and dried incorrectly.
  • Straw hats, which weaken and warp under moisture.
  • Caps with stiffened, starched, or structured brims, which lose their shape permanently.

Check the care label before doing anything. “Machine-wash” wording usually refers to a washing machine, not a dishwasher, so treat it as a caution rather than a green light. “Hand-wash only” or “dry-clean only” means exactly that. When there’s no label at all, hand washing is the safest way to clean most hats and the safest default.

Step-by-step dishwasher method for suitable caps

If your cap meets the criteria above and you still want to try a dishwasher, follow this sequence closely.

  1. Spot-treat visible stains first with a gentle detergent and a soft toothbrush.
  2. Remove any metal clips, badges, or detachable parts.
  3. Place the cap on a cap rack or frame, or secure it over an upturned cup, so it holds its shape.
  4. Load it on the top rack only, away from the heating element.
  5. Select a cool or eco cycle, never a booster or sanitise setting.
  6. Run the dishwasher empty aside from the hat.
  7. Use a tiny amount of neutral, gentle detergent, or skip detergent entirely if the cap is only lightly soiled.
  8. Remove the cap the moment the cycle ends, rather than leaving it to sit in a damp machine.
  9. Reshape it while still damp, using a shaper or a rolled towel.
  10. Air-dry away from direct heat.

Pro Tip: Skip bleach or chlorinated detergent entirely. A plain, neutral dishwasher tablet or liquid is far gentler on fabric and dye.

Detergents, dishwasher hazards and appliance care

Standard dishwasher detergents are alkaline and formulated for grease and food residue, not for fabric or dye. Appliance manuals are blunt about this risk: Haier’s user and installation manual cautions against bleach and chlorinated additives, and recommends neutral cleaning agents instead.

A few things to watch for:

  • High rinse temperatures can shrink fibres and warp plastic or buckram brims.
  • Heated drying cycles cause the same shrinkage and warping, only worse.
  • Spray-arm pressure can flatten or distort a hat’s structure during the wash.

Dishwasher drying performance varies by model and setting, and Consumer NZ’s guidance on drying issues notes that high heat raises the risk of warping for non-dishware items. Only run a hat wash in a clean machine: Consumer NZ’s dishwasher care advice recommends checking the filter and spray arms regularly, and a follow-up empty rinse cycle helps clear any leftover residue before you load dishes again.

Drying and reshaping after any wash

Never use the dishwasher’s drying cycle, and never put a hat in a tumble dryer. Heat is the single biggest cause of shrinkage and brim warping, whether it comes from a dishwasher’s heating element or a dryer drum.

Instead:

  • Place the hat on a cap shaper or an upturned bowl to hold its crown shape while it dries.
  • Support the brim with a rolled towel if it needs to stay flat.
  • Keep it away from direct sunlight, heaters, or radiators, which can fade colour and dry fabric unevenly.

Air-drying is consistently recommended over machine drying because it protects both shape and colour far better than heat ever does.

If a brim has warped slightly, gentle steam combined with reshaping on a flat surface can sometimes coax it back. Stop the moment you feel resistance or see the fabric stressing: pushing further usually causes more damage than it fixes.

Damp cap brim being gently reshaped

Pro Tip: Reshape a hat while it’s still damp. Once fabric dries into a warped shape, it’s much harder to correct.

Safe alternatives to the dishwasher

Hand washing remains the lowest-risk option for almost every hat type.

  1. Fill a basin with lukewarm water and a small amount of gentle detergent.
  2. Submerge the hat for a short soak, no more than a few minutes.
  3. Swish it gently rather than scrubbing or wringing.
  4. Rinse thoroughly with clean lukewarm water.
  5. Air-dry on a shaper, away from direct heat.

For odour and stains without a full wash, enzyme-based pre-treaters, diluted vinegar, or a baking soda paste lift sweat and smell without bleaching agents or harsh chemicals. A guide to removing sweat stains covers this pretreatment step in more detail.

Structured or delicate hats, including fedoras and leather pieces, do better with a dedicated cap-washer frame for support, or a trip to a professional cleaner who handles headwear specifically.

Expert tips and material-specific notes

Different hat materials call for different handling, and mixing them up is the fastest way to ruin a favourite piece.

  • Knitted wool beanies need a hand-wash only approach, with reshaping done immediately after rinsing.
  • Cotton baseball-style caps generally tolerate a gentle wash better than any other category.
  • Leather hats should be spot-cleaned or handed to a specialist rather than washed.

For leather and finished surfaces, a useful rule is to stop after three passes when spot-cleaning, since repeated scrubbing wears down the finish faster than dirt does. Our hat care checklist covers the full routine for washing, drying, and storage across materials.

Practical perspective: when to replace rather than repair

A hat with a permanently warped brim, fibres that have broken down, or an odour that won’t lift after proper washing has reached the end of its useful life. At that point, repeated risky washes cost more time and effort than they’re worth, and professional cleaning or replacement often works out cheaper in the long run. Buying hats built from care-friendly, washable materials from the start avoids this cycle altogether.

— Urban

Urban Caps: care-friendly hat options and care resources

Knitted Wool Female Fisherman Hat

Not every hat is worth the risk of a wash gone wrong, so choosing the right one from the start saves you the hassle later. Our Woolen Knit Beanie and Knitted Wool Female Fisherman Hat are both hand-wash only, built to hold shape through gentle care rather than a machine. The Striped Fisherman Beanie follows the same rule: cool water, no agitation, reshape while damp.

If you’re after something that handles everyday wear and easier cleaning, our Baseball Caps collection suits a gentle wash better than wool or leather ever will. Browse our BEANIES range, or check the hat care checklist for material-specific routines before you wash anything new.

Urban Caps: care-friendly hat options and care resources — overview diagram

Sources

This guide draws on Cold Power’s hat-cleaning advice, Consumer NZ’s dishwasher drying guidance, and manufacturer manuals from Haier and Fisher & Paykel.

FAQ

Can you clean a hat in the dishwasher?

Some unstructured, colourfast cotton or polyester caps can handle a cool, empty top-rack cycle with minimal detergent. Wool, leather, straw, and structured-brim hats should never go in a dishwasher, since heat and agitation cause shrinkage and warping.

What is the best way to clean a hat without ruining it?

Hand washing in lukewarm water with a gentle detergent is the safest method for most hats, since it avoids the heat and pressure that damage shape and colour. Spot-treat stains first, then air-dry on a shaper rather than using any machine drying.

How do I dry a hat after washing it in the dishwasher?

Never use the dishwasher’s drying cycle or a tumble dryer. Place the hat on a cap shaper or rounded form away from direct heat and sunlight, and let it air-dry fully before wearing it again.

What detergent should I use to wash hats in the dishwasher?

Use only a small amount of neutral, gentle dishwasher detergent, or none at all if the hat is lightly soiled. Avoid bleach and chlorinated detergents entirely, since appliance manuals explicitly warn against these on delicate materials.

Back to blog