More than one way...
My niece worked at specialty steel fabricator. When they replaced a bunch of PCs, they took the drives out to the fabrication yard, neatly laid them out on the ground and then brought over a crane with a "magnetic hook" rated for 50 tons. Lowered the hook over the drives and turned in on.
Apparently, this caused all the drives to stand up on end and wave back and forth until the hook was turned off.
Checking random drives afterwards showed nothing on them, not even formatting.