If you are looking for a command line way to remove all .svn folders in a directory tree, the correct answer here is: Don’t.
As it turns out, all you need to do is run an SVN Export command and that will create a clean directory tree for you, hastle free. Here’s an example
$ svn export svnProject myExportWithoutSnvFiles
Then you can just ignore or remove the svn directory tree and keep the new one.