When I decide that I no longer need a file or folder on my computer but it's synced to Google Drive (the Cloud), and I want to keep a copy of on Google Drive (in the Cloud), I simply log into Google Drive through my browser, find that file or folder, and move it out of the synced folder to where it won't be synced with my computer. That way nothing I do on my computer will affect it on Google Drive. It will automatically be deleted from my computer but if I need it again I can either download it manually from Google Drive or move it back into a synced folder (or sync the folder it's in). Since it no longer exists down here on Earth, it's only in danger if Google Drive loses it, I stop paying Google for my storage and they, rightfully, delete it, or I delete it from Google Drive myself and empty my trash.