Pastry brushes are widely available and inexpensive; make sure you have one at least one brush dedicated for non-savory foods—don't use your favorite BBQ brush for your candies! The rules should be butter only with no exposure to garlic or other items you wouldn't want in your chocolate.
My most common use is for a pastry brush is to brush down the sides of the pot with water while boiling corn syrup and sugar for caramels. Brushing the sides helps prevent crystallization, which will negatively affect the texture of your caramel.
