Kroil is a penetrating oil designed to loosen rusted or stuck parts. It is commonly used in automotive, industrial, and home repair applications. The formula works by seeping into tight spaces, breaking down rust and corrosion, which makes it easier to remove bolts, nuts, and other fasteners. Kroil is often favored for its effectiveness and ability to work quickly. It can be applied using a spray nozzle or a dropper, allowing for precise application. Many users appreciate its versatility, as it can also be used for lubricating moving parts and preventing future rust formation.