to delete .svn files and folders using Windows Batch Script you can use the following snippet.
Sample Windows Batch Script
FOR /R "C:\Users\CodeSnippets.Fesslersoft.de\Documents\Visual Studio 2013\Projects\ConsoleApplication" %%X IN (.svn) DO (RD /S /Q "%%X" 2>nul)
Replace C:\Users\CodeSnippets.Fesslersoft.de\Documents\Visual Studio 2013\Projects\ConsoleApplication with your Solution’s Path.