Why do this?
Simple, sometimes the SVN server, because of wrong file permissions, just errors out completely and you need a quick way to delete all the folders it created.
I'm sure you don't want to do remove all the ".svn" folders manually so read the solutions below, based on your Operating System :
Linux
You need to run this command in the folder you want the .svn entries cleared.
find . -name ".svn" -type d -exec rm -rf {} ;
What it does is basically ... search in the current folder and all its subfolders for all folders called ".svn" and remove them.
Windows XP/Vista/7/Other versions
Open Notepad and copy & paste the line below in it :
FOR /F “tokens=*” %%G IN (’DIR /B /AD /S *.svn*’) DO RMDIR /S /Q %%G
then save the file with this name "clear_svn.bat", put it in the folder you want the .svn entries cleared and double click it. That's all.