If I understand you right, you'll have a string with mixed numbers and letters. Using the regular string functions will still work. They won't care what the characters in the string represent. For instance:
string MyString = "¸¶¹¹,example⌐╙∙√∞∟";
if(MyString.Contains("example"))
{
MyString = MyString.Replace("example","and");
}
MyString = "¸¶¹¹,and⌐╙∙√∞∟" after the replace method is called.