using System;
 
public class Test
{
    public static void Main()
    {   
        string msg= "=?windows-1258?B?UkU6IFRyIDogUGxhbiBkZSBjb250aW51aXTpIGQnYWN0aXZpdOkgZGVz?= =?windows-1258?B?IHNlcnZldXJzIFdlYiBHb1ZveWFnZXN=?=";
        string[] charSetOccurences = msg.Split(new string[]{ " " }, StringSplitOptions.None);
        foreach (string s in charSetOccurences)
        {
            string charSet = s.Replace("=?", "").Replace("?B?", "").Replace("?b?", "");
            Console.WriteLine(charSet);
        }
    }
}

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