I have the following function but I want it to do the opposite eg return the bad chars not the ones I specify

This function lets you specify a two strings. The string you want to parse and a string of chars that you would like to keep from the first string specified - The edited string is returned

```
Function GETALPHANUMERIC(text, str_all)

 For lenstr = 1 To Len(text)
     If InStr(str_all, LCase(Mid(text, lenstr, 1))) Then
         GETALPHANUMERIC = GETALPHANUMERIC & Mid(text, lenstr, 1)
     End If
 Next

 End Function

```

Thanks
Rob