You can archive a collection by clicking on the three dots menu and selecting archive.
To review an archived collection or un-archive it, find the filter button at the top of your collections screen. At the bottom of the filter menu, you’ll see “Archived”. In the drop down menu, you can select “Include Archived” or “Only Archived”. Hit submit. You’ll now see a master list of either all of your collections or only your archived collections. Click on the three dots menu on the right side of your collection bar and select “Un-archive”. Your un-archived Collection will now show up in your main Collections menu.