How do I remove a folder from being source controlled with TortoiseSVN?
The TortoiseSVN menu has an Export option which will give you a copy of the folder detached from the repository. Alternatively, you can right-click + drag a folder and pick either "SVN Export to here" or "SVN Export all to here".
"Export all" is equivalent to selecting "Export unversioned files too" in the Export dialog, which will effectively clone the working copy without the .svn folders.