Road debris and high-pressure washers bend the thin aluminum fins of A/C condensers. Bent fins block the flow of air, which stops the system from shedding heat. An A/C fin comb resolves this. It features a wheel of plastic or metal teeth of different spacing sizes. You count the fins per inch on your condenser, match the tool head, and draw the comb through the bent sections. This straightens the fins and restores full airflow.
Using a screwdriver or knife is risky. The sharp edges can easily slice through the thin metal tubes carrying the pressurized refrigerant, causing a major leak. The fin comb has rounded teeth designed to slide safely along the channels without gouging the aluminum.