1. Archiving an Activity
You can archive any activity in your library so that it will not longer be visible in the library. While viewing your library, click the three dot menu (...) below the thumbnail of the activity, and select archive. The activity will no longer be visible in that library.
2. Viewing Archived Activities
You can view archived activities by checking the Archived in the Archived dropdown menu of the Filter.
3. Un-Archiving Activities
To return an archived activity to your library, start by viewing archived activities (see above). This will switch to a view showing only archived activities in that library. To revert to seeing the unarchived activities, click the cog again and select Show Archived Activities: