Mostly just delete your company’s user profiles and the objects owned by each profile. This begins to mark the space in drives as available though it doesn’t actually erase the disk sectors.
After the general deletion process, when the objects of interest to your company are “gone” from the configuration, begin removing drives from the system configuration.
For almost all practical purposes, the data is then no longer retrievable regardless of the fact that it’s still sitting (except by serious experts, and generally not “PC” experts, but serious ones). The removed drives can’t be installed into another AS/400 without reformatting. And even if they could be, the data are scatter-loaded across all drives. Without the original complete configuration, there is no way to link the scattered fragments back together.
Also, the drives use a sector size that’s incompatible with other systems. Some drive models are <b>possible</b> to install physically on some other systems, but the drives must go through a low-level formatting to restructure the sectors.
However, just in case… if you wish, you can pull the drives and reinsert them into different slots and start adding them back into your system’s configuration. When you do that, the system will require a format operation. (Actually, I don’t think the need to be reslotted, but it only takes a few minutes.)
Overall, once you simply delete the libraries, you’re probably done. The remaining steps you take simply add layers for different officers of your company. If it’s required, go ahead and do the steps.