After going back to online-only

Will the physical copies of the folders be removed from hard disk after switching from offline to online-only? It does not look like they are removed as gigs of space is still taken up. Are we supposed to go in to a place on drive c and delete them manually? If so, where are they located on the drive? This should not even be a question to ask/issue to raise but here I am. Can someone please help to resolve?