Solution: The Unique Tag Cleaner

using System.Collections.Generic;
using BlogEngine;
TagProcessor processor = new();
List<string> messyTags = ["web", "c#", "coding", "web", "api", "c#"];
List<string> cleanTags = processor.CleanTags(messyTags);
foreach (string tag in cleanTags)
{
    Console.WriteLine(tag);
}