[header] How to test a carbon monoxide detector [title] Purchase smoke detector tester spray. [step] Canned smoke, also known as smoke detector spray, can also be used to test your carbon monoxide detector. You can find this spray at most home improvement stores, or you can purchase it online. 
One can costs between $5-$10 usd and will usually last for a few years. [substeps] Canned smoke is an extremely flammable aerosol and should be kept out of sunlight or temperatures above 122 ° f (50 ° c).