You only need two very basic things for this trick to work beautifully. You need a pot of boiling water and a small oven safe bowl filled with plain ammonia.
An important note here: You want to make sure your kitchen has a little bit of airflow since ammonia has a very strong scent. Open a nearby window or turn on your stove exhaust fan before you start. It is a very cheap solution that works great in place of expensive specialty cleaners.