Outdoor sandals and water shoes are subjected to a uniquely punishing combination of water, dirt, sweat, and bacteria that few other footwear types endure. A pair of Chaco Z/Cloud sandals might be worn through a river crossing at 10 AM, baked in 35C sun on a rock at noon, submerged again at 2 PM, and left damp in a tent vestibule overnight. This cycle breeds bacteria, degrades materials, and produces the distinctive odor that announces the presence of well-used sandals from across a campsite. Proper care keeps sandals functional, odor-free, and intact for years longer than neglect.
The Materials: What You Are Actually Cleaning
Before choosing a cleaning method, identify what your sandals are made of:
Straps: Most outdoor sandals use polyester webbing. Chaco uses a specific jacquard-weave polyester webbing treated with a water-repellent finish. Teva uses standard nylon or polyester webbing with a slightly softer hand. Keen sandals use polyester webbing with a neoprene or synthetic lining at contact points. Webbing is machine-washable but degrades faster when repeatedly machine-washed due to mechanical agitation.
Footbed: The surface your foot rests on. Chaco uses polyurethane (PU) with a textured pattern called LUVSEAT. Teva uses EVA (ethylene-vinyl acetate) foam. Keen uses a combination of PU and EVA with a microfiber or mesh top layer. The footbed material matters because EVA absorbs water and cleaning solutions more readily than PU, and EVA is less resistant to harsh cleaning chemicals.
Midsole and outsole: Chaco uses PU midsoles with their ChacoGrip rubber outsole (a non-marking rubber compound). Teva uses EVA midsoles with Durabrasion rubber. Keen uses PU or EVA midsoles with non-marking rubber outsoles. Cleaning products that are safe for the footbed material are generally safe for these components.
Toe protection (Keen): Keen's signature toe bumper is made of TPU (thermoplastic polyurethane) or rubber. It is resistant to most cleaning approaches but can separate from the upper if flexed aggressively while cold or if the adhesive degrades from heat exposure.
Regular Cleaning: The Bucket Method
For sandals and water shoes that are dirty but not odorous:
- Fill a bucket or sink with lukewarm water. Add a small amount of mild liquid soap (Dr. Bronner's unscented, a teaspoon per gallon). Do not use laundry detergent -- it contains optical brighteners and enzymes that can degrade EVA foam and leave residue in PU.
- Submerge the sandals and agitate them. Use a soft-bristled brush (an old toothbrush or a dedicated shoe brush) to scrub the following areas: the footbed (especially the textured pattern where dirt packs in), the strap-to-sole attachment points (where grit accumulates and accelerates wear), the buckles and hardware, and the outsole tread.
- Pay particular attention to the area where the straps pass through the sole -- known as the "ladder lock" area on Chacos, where the continuous strap threads through the sole and adjusts. This is where grit concentrates and where strap wear is most visible.
- Rinse thoroughly with clean water. Soap residue attracts dirt and can irritate skin when you wear the sandals next.
- Dry by placing the sandals in a well-ventilated area out of direct sunlight. Do not dry in a dryer, on a radiator, or in direct sun for more than an hour or two. Direct sun accelerates PU and EVA degradation and causes strap fading. The ideal drying location is a shady, breezy spot outdoors or a well-ventilated room indoors.
- Turn sandals over after several hours to ensure both sides dry completely. In humid conditions, complete drying may take 24 hours.
Odor Control: The Fundamental Problem
Sandals develop odor because bacteria colonize the footbed and straps. The bacteria metabolize sweat residue, dead skin cells, and environmental organic matter, and their metabolic waste products are what smell. Cleaning removes the bacteria's food supply and kills a portion of the bacteria. More aggressive methods kill the remaining bacteria.
Prevention (more effective than cure):
- Rinse sandals with fresh water after every use, especially after salt water or muddy water. A 10-second rinse at a camp spigot or stream prevents bacteria from establishing colonies on dried-in sweat and organic matter.
- Dry sandals completely between uses. Bacteria require moisture to multiply. A sandal dried completely within 12 hours of use will have dramatically fewer bacteria than a sandal kept damp in a pack or tent.
- Alternate between two pairs if you wear sandals daily on a multi-day trip. This gives each pair a full drying day.
For sandals that already smell:
Vinegar soak. Fill a tub or bucket with a solution of 1 part white vinegar to 3 parts water. Submerge the sandals completely and let soak for 30 minutes. Vinegar (acetic acid) kills most odor-causing bacteria and does not damage polyester webbing, PU, or EVA. Rinse thoroughly afterward. The vinegar smell dissipates completely as the sandals dry. This is the most effective home treatment for sandal odor and costs pennies.
Baking soda paste. For localized odor on the footbed, make a paste of baking soda and a few drops of water. Scrub it into the footbed with a brush, let it sit for 15 minutes, and rinse. Baking soda absorbs odor compounds and is mildly abrasive, which helps remove the biofilm layer where bacteria live.
Hydrogen peroxide spray. A 3% hydrogen peroxide solution (standard drugstore concentration) sprayed lightly onto the footbed kills bacteria through oxidation. Rinse after 5 minutes. This is more aggressive than vinegar and can slightly lighten dyed webbing materials. Test on a small area of the strap first. Do not use concentrations above 3%.
Enzymatic cleaners. Products like MiraZyme (from Gear Aid, about 8 USD) or Nature's Miracle (from pet supply stores, about 10 USD) use enzymes to break down the organic matter that bacteria feed on. Soak the sandals in an enzymatic solution for 30 minutes, then rinse. This is effective for deeply saturated odors that resist vinegar treatment.
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What NOT to use for odor:
- Bleach. It degrades polyester and nylon webbing, damages PU and EVA foam, and corrodes metal hardware (buckles, D-rings, rivets).
- Boiling water. Temperatures above 60C (140F) can deform EVA foam and weaken adhesive bonds in the sole construction.
- Machine drying on any heat setting. The tumbling action and heat together can warp the sole and damage the straps.
Strap Maintenance and Adjustment
Chaco strap system. Chaco sandals use a continuous strap that threads through the sole and wraps around the foot. The strap tension is adjusted by pulling the strap through the sole channels. Over time, the strap can become difficult to adjust because grit inside the channels increases friction.
To clean sticky Chaco straps: remove the footbed insole if your model allows this (some Chaco models have a removable insole). Pull the strap back and forth through the sole channel while running water through the channel. Use a thin brush (a straw-cleaning brush or a pipe cleaner folded in half) to scrub inside the channel. The difference in strap adjustability after cleaning grit from the channels is immediately noticeable. If you feel resistance when adjusting straps, the sole channels are dirty.
Teva strap system. Teva sandals use a simpler strapping system with fewer contact points. The Velcro closure on the heel strap is the most common wear point. Sand, dirt, and lint accumulate in the hook side of the Velcro, reducing its grip. Clean Velcro by running the tip of a safety pin or a toothpick through the hook side to lift out debris. A stiff brush also works. If the Velcro has lost its grip even after cleaning, the hook fibers have worn flat (they are tiny nylon hooks that fatigue from repeated opening and closing). Velcro replacement is possible but requires sewing -- for 60 to 80 USD sandals, replacement of the sandals may be more practical.
Keen strap system. Keen sandals use a bungee-lace system on many models (the Newport H2 and the Clearwater CNX). The elastic cord that provides the closure tension loses elasticity over time, typically after 2 to 3 years of regular use. The cord can be re-tensioned by pulling the slide-lock mechanism tighter, but this reduces the range of adjustment. When the bungee no longer provides adequate tension even at its tightest setting, it should be replaced. Keen sells replacement bungee lace kits for about 5 USD.
Water Shoe Drying and Odor Control
Water shoes (Keen Newport H2, Merrell Choprock, Astral water shoes) are designed to be submerged, drained, and worn wet. Their drainage ports and mesh uppers allow water to drain quickly, but they also allow organic matter and bacteria to enter and colonize the shoe interior.
After saltwater use: Saltwater leaves salt crystals inside water shoes as the water evaporates. These crystals are abrasive and hygroscopic -- they attract moisture and keep the shoe damp longer. Rinse thoroughly with fresh water after every saltwater outing. A 30-second rinse under a faucet or in a stream is sufficient.
Drying water shoes: Remove the insole (if removable) and let both the shoe and insole dry separately. Water shoes dry fastest when air can circulate through them. Place them on their sides with the opening facing a breeze or a fan. In humid conditions, stuff loosely with newspaper and replace the newspaper after 4 hours. Do not wad the newspaper tightly -- the goal is air circulation, not absorption.
Disinfecting water shoes: Water shoes worn in warm, organically rich water (swamps, warm rivers, tropical waters) can harbor bacteria and fungi that cause skin infections. Periodic disinfection with a vinegar soak (as described above for sandals) reduces this risk. This is especially important if you or a family member has experienced athlete's foot or other fungal infections -- the organism can survive in the shoe and cause reinfection.
Preventing Material Breakdown
EVA foam compression. EVA (the foam used in Teva footbeds and most water shoe midsoles) compresses permanently under repeated load. This is why old sandals feel flatter and less cushioned. The compression is structural -- the EVA cells collapse and do not recover. Once EVA has compressed, it cannot be restored. Walking in sandals with compressed EVA increases impact stress on your feet and knees. Depending on your use, EVA footbeds in sandals last 1 to 2 years before noticeable compression. PU footbeds (Chaco) last longer, typically 3 to 5 years, because PU is a denser, more resilient material.
Delamination. The bond between the outsole and the midsole, and between the midsole and the footbed, can fail over time. Delamination typically starts at the edges, near the heel or toe, where the sole flexes most. Shoe Goo (about 6 USD) or Aquaseal FD can re-bond a partially delaminated sole to the midsole if the delaminated area is small (less than 5cm or 2 inches). Clean the delaminated area with alcohol, apply a thin layer of adhesive, press together, and clamp with tape or a heavy weight for 24 hours. If the delamination extends around more than about 25 percent of the sole perimeter, the structural bond is failing and the sandal should be replaced.
Strap fraying. Webbing straps that fray at the adjustment points or where they pass through the sole become progressively weaker. Trim frayed edges with scissors and seal the trimmed end with a lighter flame (briefly, to melt the cut edge -- do not set the strap on fire). A strap that is frayed through more than about 30 percent of its width has lost significant tensile strength and should be replaced. Chaco offers a resole and re-strap service (called ReChaco, about 50 USD) that replaces the straps, footbed, and outsole while retaining the original buckle and webbing architecture. This effectively makes the sandal new for roughly half the price.
Seasonal Storage
Sandals are seasonal gear in temperate climates. Before storing for winter:
- Clean thoroughly (the bucket method described above, plus vinegar soak if odor is present).
- Dry completely (48 hours minimum in a well-ventilated space). Any moisture sealed into a storage bin for 5 months guarantees mildew.
- Store sandals flat, not folded or compressed. Do not place heavy boxes on top of sandals -- this compresses the footbed foam.
- Store in a breathable bag or box (cardboard is fine if the storage area is dry; a fabric bag is better). Do not store in a sealed plastic bag, as this traps any residual moisture and promotes mildew.
- Store in a cool, dry place away from direct light and away from heat sources. Basements and attics are poor storage environments for the same reasons they are poor for other outdoor gear: humidity in basements, heat in attics.
Quick Reference: Cleaning by Sandal Type
| Sandal Type | Cleaning Method | Avoid |
|---|
| Chaco (PU footbed) | Bucket wash with mild soap; vinegar soak for odor | Bleach, machine washing, dryer |
| Teva (EVA footbed) | Bucket wash with mild soap; baking soda for odor | Bleach, prolonged soaking (EVA absorbs water) |
| Keen water shoes | Bucket wash with mild soap; vinegar disinfectant | Bleach, machine washing, dryer heat |
| Crocs/foam clogs | Rinse with water; soap optional | Bleach (discolors foam permanently) |
| Leather sandals | Damp cloth wipe; leather conditioner | Full submersion (damages leather), heat drying |
The 30 minutes spent cleaning sandals properly three times per season -- once at the start, once mid-season, and once before storage -- is returned many times over in longevity and the simple pleasure of putting on sandals that do not smell.