Basic clean up Q: delete FOLDERS, or delete BIN CONTENT prior to that?

After finishing a project I consolidate to a new HDD, and then drag the new masterclips & edits in new bins named CONSOLIDATED.

Now I have to get rid of all the old stuff in the project:
First, I delete all the old Media Files (I do that on Windows level, because they are always in project-specific folders).
Then, back in the Avid, I open every FOLDER and sub-FOLDER and sub-sub-FOLDER and, finally in the bin, I delete all the old Masterclips, Sequences, Subclips, gfx, Titles etc...

My question:

* Is it ok to directly delete the "first-level" FOLDERS (mostly only 5 in my case)?
* Or do I have to delete every BINS's content first? (which is what I'm doing since 15+ YEARS!!).

Note that all the media is gone anyway at this cleaning stage...

TIA, happy weekend