Canned air is a portable can of pressurized gas used to blow dust and debris off electronics, keyboards, sensors, and other small parts. In security work, it matters because clean surfaces are easier to inspect, and dust can hide tamper evidence, block vents, or cause shorts and overheating in sensitive hardware.
Defenders use canned air in labs, repair benches, and incident response to clean devices before opening them, photographing them, or removing storage media. Attackers can use the same tool during a physical intrusion to clear dust from ports, labels, screws, or hidden seams before plugging in hardware or opening a case. It is useful, but it is not harmless: holding the can upside down can spray liquid propellant, and strong blasts can move debris deeper into a device or damage delicate parts.