To remove a rounded lug nut, purchase a rounded-lug-nut-removal tool from a local auto repair shop. Many lug-nut-removal tools are sold with a set of socket-type ends in various sizes. To use the lug-nut-removal tool, choose the appropriately sized socket from the set and twist it onto the lug nut. Once the removal tool is firmly in place, turn the socket to remove the lug nut.
In an emergency situation, it is possible to use a chisel, screwdriver and hammer to remove a rounded lug nut. To use the chisel method to remove a lug nut, place a small, sharp chisel on the outer edge of the lug nut, and hit the chisel with a hammer to form a small notch. Insert a flat screwdriver into the notch and loosen the lug bolt until it can be removed by hand.
Rounded lug nuts can also be removed with a grinder and tire iron. Use the handheld grinder to create two flat sides on the lug nut, and remove the nut with a tire iron. Do not touch the surrounding areas with the grinder, and wear safety goggles during the removal process. Take the vehicle to a mechanic after removing the nut to ensure no further damage has occurred during the removal process.