Fold the towel twice to produce a soft cushion. The towel will protect your work surface and will provide some surface protection for the magnetized metal object during demagnetization.
Test for the presence of a magnetic field in the object using a compass. The south of the compass needle will align with the object's magnetic north pole. Rotate your object. The compass needle will follow the movement of a magnetized object.
Place the magnetized metal object in the center of the folded towel. Position the object so that the long axis of the object is not aligned with the north-south poles of the earth. To find the north-south poles of the earth, move a few meters away from the magnetized object before using your compass. Away from the magnetized object, the compass needle will align with the earth's magnetic field.
Use the hammer to strike the metallic regions of the magnetized object. Take care to avoid any parts of the object that may contain ceramic or which appear fragile. Strike the object a minimum of 20 times with light to moderate force. It is not necessary to use excessive force that may damage the object. The jarring caused by striking the object with the hammer will result in misalignment of the magnetic domains.
Repeat the test for the presence of a magnetic field described in Step 2 to determine if the demagnetization procedure was successful. If the compass needle aligns with the magnetic field of the object and follows the movement of the object, the object is still magnetized. Repeat step 4 until the compass needle does not appear to be influenced by a magnetic field associated with the object. The object is demagnetized when it no longer influences the direction of the compass needle.