using System;

using System.Text;

public class Program

{

    private static string Sanitize(string inputString) {

        return Encoding.ASCII.GetString(

            Encoding.Convert(

                Encoding.UTF8,

                Encoding.GetEncoding(

                    Encoding.ASCII.EncodingName,

                    new EncoderReplacementFallback(string.Empty),

                    new DecoderExceptionFallback()

                    ),

                Encoding.UTF8.GetBytes(inputString)

            )

        );  

    }

    private static void TestString(string str) {

        Console.WriteLine("{0} -> {1}", str, Sanitize(str));    

    }

    public static void Main()

    {

        TestString("Räksmörgås");

        TestString("—emdash");

        TestString("“smart quotes”");

        TestString("region’s land it's");

        TestString("Accented áéíóúüñ¿¡ÁÉÍÓÚÜÑ chars");

    }

}