Use a mortar and pestle to pound the chilies and garlic into a rough paste.

Cook the vinegar, sugar, and salt on medium heat until all the sugar is dissolved.

Increase the heat and bring to a boil, once it is boiling, add the chili and garlic mixture. Reduce heat to a simmer and stir, simmer for 15-20 minutes or until the sauce reaches your desirable thickness.

Remove from heat and pour the sauce into a sterilized jar. Let it cool down to room temperature, then cover and refrigerate. Can be stored in the fridge for up to a month.