I usually use a Tropic Salad Dressing–size bottle and only Hawaiian chili peppers. I’ve tried other peppers, but it’s just not the same, if you have to substitute, Thai are best.
First, sterilize the bottle with boiling water or in the dishwasher.
Add about one inch of Hawaiian chili peppers (roughly 50–75 peppers), with the stems removed. Sprinkle in about 2 teaspoons of Hawaiian salt. Smash the peppers—really smash them up with chopsticks or do it before you add to the bottle. The salt helps break them down.
Pour in white vinegar just until the smashed peppers are covered, then fill the rest of the bottle with cooled, boiled water.
If you like garlic, you can add it, or really any flavor you enjoy, like soy sauce or pineapple juice. Keep it simple or make it your own.