Remove all non-ASCII characters from string

Question

I have a C# routine that imports data from a CSV file, matches it against a database and then rewrites it to a file. The source file seems to have a few non-ASCII characters

Answer 1

Do it all at once

public string ReturnCleanASCII(string s)
{
    StringBuilder sb = new StringBuilder(s.Length);
    foreach(char c in s)
    {
       if((int)c > 127) // you probably don't want 127 either
          continue;
       if((int)c < 32)  // I bet you don't want control characters 
          continue;
       if(c == ',')
          continue;
       if(c == '"')
          continue;
       sb.Append(c);
    }
    return sb.ToString();
}