Re Purposing old nas drives

Hi sorry if this has been asked previously i have a number of drives which i have replaced from my ex 4 nas (16TB in total ) i have upgraded them to larger drives. I am wanting to reformat the older 2TB drives which have now come out of the nas to reuse on pc or mac my question is how do i reformat the drives so they are usable within windows or osx?

Basically, NAS hard drives are hardware encrypted and need an enclosure to access the data. But you can try to connect these drives directly to the computer and erase them to free all the data sectors in the hard drive. After this, you will get initialize option to get started.