HFM - Best practices for deleting security classes

Forgive me if this issue has been discussed before but a search didn't call up anything specific.

We're running HFM 11.1.2.4.204, and we have an app with ~8 years of data.

There are 40 security classes, some of which are no longer used. But, they may have been used in the past, and assigned to old posted Journal Entries, for example.

I deleted 8 security classes last night (in the TEST system, fortunately) using the Shared Services module, and that completed error-free. I then tried to open one of our three apps, and experienced a lockup of the workspace.

After the nightly backups, everything started up fine this morning, but until that happened, scary thoughts came to mind. I checked the metadata file, and made sure that there were no references to any of the eight deleted security classes. But extracting all of the posted journals, for all of the years and scenarios in the database, to check for those same 8 security classes, would be a big job.