using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        var text = "";

        for (int i = 0; i <= 31; i++) {

            text += " " + i + "_" + (char) i;

        }

        text += " " + 127 + "_" + (char) 127;

        text += " Ç";

        Console.WriteLine("Original text: '" + text + "'");

        var newtext = Regex.Replace(text, "[\x0-\x1F]", "");

        Console.WriteLine("New text: '" + newtext + "'");

    }

}