What Does Dishwasher Cleaner Do? | Machine Maintenance Explained

A dishwasher that smells musty or leaves spots on glassware often isn’t broken — it’s just dirty inside. Dishwasher cleaner targets the hidden deposits that regular detergent leaves behind in spray arms, filters, and hoses. Unlike dish soap, which cleans your plates, this product cleans the machine itself. Running it once a month keeps internal parts working efficiently and extends the appliance’s lifespan.

What Dishwasher Cleaner Actually Removes

Over months of use, hard-water minerals, grease, and detergent scum accumulate in places you never see. Consumer Reports recommends a citric-acid-based cleaner to dissolve these deposits, and Finish’s official dishwasher cleaner page outlines the same principle: the product targets hidden grease and limescale from internal surfaces that dishwashing detergent alone cannot reach.

Three types of buildup a cleaner addresses:

• Limescale and mineral scale — white crusty deposits from hard water that can clog spray-arm jets and slow drainage.
• Grease and soap residue — a sticky film that traps food particles and bacteria, often the root of musty odors.
• Biofilm — a slimy layer formed by microbes in damp, dark spaces like the drain hose and filter area.

If you are ready to buy a cleaner, our tested roundup of the best dishwasher cleaners breaks down which products work for different types of buildup and machine brands.

How To Use It The Right Way

The exact steps depend on whether your cleaner comes as a tablet, pod, or bottle, but all share the same basic rule: the dishwasher must be empty and no dish detergent should be added.

• Tablets and pods: Place one tablet in the detergent dispenser and close it. For heavy buildup, add a second tablet on the bottom of the empty tub. Run a normal cycle with the hottest water setting available.
• Bottle-style cleaners: Remove any seal or plastic cap as directed on the label. Place the bottle upside down in the utensil basket or on the bottom rack. Select the hottest, longest cycle — usually labeled “Intensive,” “Pots & Pans,” or “Sanitize.”

Once the cycle finishes, open the door and let the interior air dry completely. A quick wipe of the rubber door gasket after cleaning helps prevent mold from returning.

Common Mistakes That Waste The Effort

Even with the right product, a few errors can leave your dishwasher still dirty. The most frequent mistake is running the cleaner with dishes inside — the cleaner needs an empty tub to recirculate through every internal corner. Another is adding dish detergent to a cleaning cycle, which creates excess suds and can damage the machine. Forgetting to scrape large food bits from the filter area beforehand also blocks the cleaner from reaching the drain hose.

If you have been using vinegar or baking soda as a homemade alternative, Consumer Reports advises switching to a dedicated citric-acid-based cleaner instead, because those DIY methods are less effective at breaking down mineral scale and can sometimes damage rubber seals over time.

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