how to safely destroy all info on hard drives?

Disks encrypted with FileVault do not have to be secure-erased, as everything is low level “garbled” using a password, and Disk Utility doesn’t let you secure erase SSD drives.

Destroying drives is much faster that secure-erasing.

Not sure what you mean by "safely" but…

How to erase a disk for Mac - Apple Support

If you are worried about somebody using special data recovery methods to get deleted data from your drive, use Disk Utility's Security Options button and select a security level. One pass, or one position to the right on the slider, is sufficient. It can take several hours.