string strText = "djflwe325443(*^*%^*jfl";
ArrayList arrayList = new ArrayList();
for (int i = 0; i < strText.Length; i++)
{
if (!Char.IsLetterOrDigit(strText, i))
{
arrayList.Add(strText[i]);
}
}
foreach (Char ch in arrayList)
{
strText = strText.Replace(ch, ' ');
}