Comet cleanser can kill individual ants on contact, but it won’t solve an ant problem. The abrasive powder and chemical ingredients (including bleach) are harsh enough to kill ants that walk through it or get dusted with it directly. However, this is purely surface-level killing, and it comes with real risks to your household that make it a poor choice compared to actual ant control products.
Why Comet Kills Ants but Doesn’t Fix the Problem
When you sprinkle Comet on ants, the powder’s alkaline chemicals and abrasive particles can dehydrate and poison the insects you see. But the ants you see are just workers, a small fraction of the colony. The queen, who produces all new ants, stays hidden deep in the nest and never comes into contact with your kitchen counter.
This is the core limitation of any contact-kill approach. Surface treatments only eliminate the workers that happen to walk through the product. Worse, strong-smelling chemical cleaners like Comet tend to repel ants rather than kill them. That doesn’t eliminate the colony. It just reroutes the ants to a different entry point in your home. You may notice fewer ants in one spot only to find them appearing somewhere else days later.
What Actually Eliminates an Ant Colony
Ant baits work on the opposite principle from contact killers. Instead of repelling or killing workers on the spot, baits attract foraging ants with a food source laced with a slow-acting toxin. The workers carry the bait back to the nest, feed it to other ants and the queen, and the colony dies from the inside out. This process takes days or sometimes weeks, but it targets the source of the problem rather than just the visible symptoms.
One important detail: if you spray or dust Comet (or any other cleaner) near a bait station, you’ll contaminate the bait and repel ants away from it. Using a cleaner and a bait in the same area actually undermines the more effective solution. If you’re putting out bait traps, clean the area with plain water only, and resist the urge to kill the ants you see walking toward the bait. Those workers are doing exactly what you want them to do.
Health Risks of Using Comet as Pest Control
Comet is formulated to clean sinks and tubs, not to sit exposed on floors, baseboards, or countertops where ants travel. Using it as a pesticide means leaving chemical residue in areas where people and pets live, which creates hazards that registered ant products are specifically designed to minimize.
Comet contains sodium hypochlorite (bleach) and formaldehyde, both of which pose risks when left accessible. About 8.3% of calls to the ASPCA Animal Poison Control Center involve household cleaning products. Pets that walk across cleaning powder can absorb chemicals through their paw pads or ingest them while grooming. Signs of exposure in pets include drooling, vomiting, diarrhea, and lethargy. Skin contact can cause redness, sores, or chemical burns. Inhaling the fine powder can trigger coughing, sneezing, and difficulty breathing in both pets and people.
Children face similar risks. Comet powder scattered along a baseboard or doorway is at floor level, exactly where toddlers crawl and put their hands in their mouths. The product’s label directs users to rinse surfaces thoroughly after cleaning for good reason.
Comet Is Not a Registered Pesticide
The EPA requires any product marketed to kill pests to undergo toxicity review, exposure assessment, and effectiveness testing before it can be registered and sold for that purpose. Comet has no such registration. It’s approved as a cleaning product, not a pest control product. This means no one has tested whether it works reliably against ants, at what concentration, or what the exposure risks are when it’s used that way.
Registered ant baits and insecticides, by contrast, have been evaluated for both effectiveness and safety when used as directed. Gel baits, bait stations, and even food-grade diatomaceous earth all offer better results with lower risk than repurposing a bathroom cleanser.
Better Alternatives for Ant Control
If you’re seeing a trail of ants in your home, the most effective approach combines two steps: remove what’s attracting them and deploy bait to kill the colony.
- Clean up food sources. Wipe down surfaces with soapy water (not chemical cleaners near bait), store food in sealed containers, and don’t leave pet food out overnight.
- Use ant bait stations or gel bait. Place them along the trails you’ve observed. Let ants feed freely for several days without disturbing them.
- Seal entry points. Caulk gaps around windows, doors, and where pipes enter walls.
- Try diatomaceous earth for perimeter use. Food-grade diatomaceous earth damages insects’ outer coating and dehydrates them. It’s low-toxicity for households with pets and children, and it works through physical action rather than chemical exposure.
For persistent infestations, particularly with species like carpenter ants that nest inside walls, a pest control professional can locate the colony and treat it directly. A $5 box of bait stations from any hardware store handles most kitchen ant problems within a week or two.