How do you purge unused content in unreal 5.0?

We used the Matrix city to make our scene for class and it quickly bloated out of control. We deleted a bunch of stuff from map in outliner but it is still in our content browser. We are having a lot of trouble deleting stuff without breaking the objects and I tried to migrate the map and it crashed (we have 64 GB of RAM).
Is there some plugin for Unreal Engine 5 that just purges unused assets?