In a previous post I introduced a tiny utility to clean up Visual Studio projects. I have introduced minor fixes to it since then, so this is the most recent version, which also deletes *.suo and *.user files and produces a report of all the files and folders that couldn't be deleted for any reason:

Imports System.IO

Module Module1
   Sub Main(ByVal args() As String)
      Console.WriteLine("VSProjCleaner tool (C) 2005 Francesco Balena, Code Archirects")
      If args.Length = 0 Then
         Console.WriteLine("Removes BIN and OBJ folders, .suo and .user files from Visual Studio projects")
         Console.WriteLine()
         Console.WriteLine(" SYNTAX: VSProjCleaner dirname")
         Console.WriteLine()
         Return
      End If
      Console.WriteLine()

      ' Use current directory if no argument has been specified
      Dim rootDir As String = Directory.GetCurrentDirectory()
      If args.Length > 0 Then rootDir = args(0)
      ' Read all the folder names in the specified directory tree
      Dim dirNames() As String = Directory.GetDirectories(rootDir, "*.*", SearchOption.AllDirectories)
      Dim errorsList As New List(Of String)

      ' delete any .suo and vbproj.user file
      For Each dir As String In dirNames
         Dim files As New List(Of String)
         files.AddRange(Directory.GetFiles(dir, "*.suo"))
         files.AddRange(Directory.GetFiles(dir, "*.user"))
         For Each fileName As String In files
            Try
               Console.Write("Deleting {0} ...", fileName)
               File.Delete(fileName)
               Console.WriteLine("DONE")
            Catch ex As Exception
               Console.WriteLine()
               Console.WriteLine(" ERROR: {0}", ex.Message)
               errorsList.Add(fileName & ": " & ex.Message)
            End Try
         Next
      Next

      ' Delete all the BIN and OBJ subdirectories
      For Each dir As String In dirNames
         Dim dirName As String = Path.GetFileName(dir).ToLower()
         If dirName = "bin" OrElse dirName = "obj" Then
            Try
               Console.Write("Deleting {0} ...", dir)
               Directory.Delete(dir, True)
               Console.WriteLine("DONE")
            Catch ex As Exception
               Console.WriteLine()
               Console.WriteLine(" ERROR: {0}", ex.Message)
               errorsList.Add(dir & ": " & ex.Message)
            End Try
         End If
      Next
      Console.WriteLine()
      Console.WriteLine(New String("-"c, 60))
      If errorsList.Count = 0 Then
         Console.WriteLine("All directories and files were removed successfully")
      Else
         Console.WriteLine("{0} directories or directories couldn't be removed", errorsList.Count)
         Console.WriteLine(New String("-"c, 60))
         For Each msg As String In errorsList
            Console.WriteLine(msg)
         Next
      End If
   End Sub
End Module

You can download the binary version here: VSProjCleaner.exe (24 KB) 
or the complete solution here: VSProjCleaner_Source.zip (15.08 KB)

Using this tool couldn't be simpler: just run it from the command window and pass a folder name as an argument, enclosing it in double quotes if it contains spaces:
                            VSPROJCLEARNER "c:\my projects\testproj"
The tool recursively visits all the folders and deletes all BIN and OBJ directories, and deletes *.suo and *.user files. At the end of the process it lists all the folders and files that couldn't be removed, if any.

DISCLAIMER: I have tested this code against my own projects and it always worked correctly, but I don't should be held responsible for any loss of important files (for example, a .user file that has nothing to do with a Visual Studio project.). For this reason, I urge you to apply this tool only to a COPY of your projects