Clean Unwanted Characters From a String

'Function to clean all characters but A-Z, a-z, and 0123456789 
'When I don't use Regular Expressions I use this function to put 
'only the characters I want into a string. It is very useful 
'for password generation. Look up the Dec number on an ASCII 
'chart and use this for many things. 
 
Public Function CleanString(ByVal strDirty As String) As String 
 
Dim strLen As String 
Dim strCounter As Integer 
Dim strClean As String 
 
strLen = strDirty.Length 
strClean = "" 
 For strCounter = 1 To strLen 
 Select Case Asc(Mid(strDirty, strCounter, 1)) 
     Case 65 To 90 'A-Z 
       strClean = strClean & Mid(strDirty, strCounter, 1) 
     Case 97 To 122 'a-z 
       strClean = strClean & Mid(strDirty, strCounter, 1) 
    Case 48 To 57 ' 0123456789 
       strClean = strClean & Mid(strDirty, strCounter, 1) 
    Case Else 
       'All other characters are stripped out 
 End Select 
 Next 
 
Return LCase(strClean) 
 
End Function