Cartoon illustration of a cockroach looking at its leg covered with insecticidal dust

Killing Roaches with Insecticidal Dust

Active Time: 1 hour
Additional Time: 5 days
Total Time: 5 days 1 hour
Difficulty: Easy

Insecticidal dust is a fine powder applied to areas that roaches frequent. It clings to their bodies, damaging the waxy coating that protects them, eventually causing them to die.

In this Roach-Free Recipe, you'll learn how to kill roaches with CimeXa, a man-made silica dust that's not only effective, but extremely safe for humans and pets. CimeXa isn't designed for wet areas, and should be targeted to cracks and crevices.

Like other dusts, it performs best when used alongside other methods, including baits, sanitation and exclusion.

Also see: A Simple 5-Step Guide For Getting Rid of Roaches.


  • CimeXa insecticidal dust, 4 oz.


  • Handheld bulb duster
  • Flashlight
  • Screwdriver
  • Latex gloves
  • Moist rag and a soft brush
  • Knee pads (optional)
  • Step stool (optional)
  • A few large Ziploc bags (optional)


A. Find Where the Roaches Hide

If you haven't done so yet, inspect your home, preferably with the help of sticky traps and a notebook, to find where roaches hide. You'll find a printable Roach-Free Recipe for that here.

B. Purchase Supplies and Read Product Labels and Instructions

  1. Purchase a 4 oz. tube of CimeXa insecticidal dust. Probably known best as a bed bug killer, CimeXa works for roaches, too.
  2. Purchase a handheld bulb duster with separate attachment tips. Though CimeXa's squeeze bottle can double as a simple duster, a specialized dusting tool will do a better job.
  3. Purchase a few pairs of latex gloves. CimeXa dust won't hurt you, but can be very drying to the skin.
  4. If you used sticky traps in a previous step to find where roaches hide, purchase a few large Ziploc bags to safely throw used sticky traps away.
  5. Read the instructions that accompanied your dusting tool, and as with any insecticide, thoroughly read CimeXa's product label.

C. Prepare Your Duster

  1. Find a room with minimal airflow (to avoid blowing the dust around) and put on latex gloves.
  2. Fill your duster half full with CimeXa and secure the cap to seal.

D. Lay Down Dust

Insecticidal dust should be deposited in a super-thin film, so light that you barely see it coming from the duster's tip. When using a bulb duster, tilt the tool at a slight angle when you squeeze, and shake it a little between puffs, which helps the dust to flow. Expect to get about 50 squeezes from 2 ounces of dust, 50 more from the remaining CimeXa in your bottle.

  1. Scan a 5-6 square foot area around an area where roaches travel or infest. This could be indirect signs of roaches such as droppings, or roaches captured at that location in a sticky trap.
  2. Scan first for cracks and crevices, then select a duster tip that could fit at least partially inside. Do a single light squeeze of your duster in each crack, pulling the tip out before the duster is allowed to fill again with air.
  3. Look for nearby electrical boxes and remove the face plates with your screwdriver. Do a single light squeeze (with a plastic tip) inside the void, then pry the exposed sheet rock up slightly with the screwdriver and squeeze two more puffs of dust into the wall void itself.
  4. Scan for nearby baseboards and look for gaps between the baseboard and the floor. Select a duster tip that fits in that gap and squeeze a puff of dust every 12 inches or so.
  5. Scan for exposed pipes and plumbing and look for where pipes enter walls. Squeeze a puff of dust into the wall voids and around the base of the pipes themselves.
  6. Scan for voids and gaps in and around appliances and squeeze dust inside.
  7. For an extensive list of potential cockroach hot spots, click here.

E. Clean up

  1. Use a brush and a moist rag to wipe up any powder that spills from cracks and gaps. At worst the small amount of powder is unsightly, but won't harm you or cause stains.
  2. If you've used Ziploc bags to bag up sticky traps, seal and dispose of them. You can also drop them in the freezer for a few hours to kill any living cockroaches or their eggs.
  3. Store your duster and unused dust in a dry place out of reach of children.
  4. Wash your hands and clothing.

Suggested next step: Kill Roaches as they Feed with Edible Gel Bait.

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