Usually there is a single source, so you have to clean out the cabinets/pantry etc and find where they are "nesting" and get rid of the source. We try to keep everything in glass canning jars. Thoroughly clean the cabinets and shelves with
white vinegar. We add a few drops of essential oils such as
Peppermint,
Tea Tree,
Eucalyptus and/or
Lemon Myrtle, but vinegar probably works alone. These essential oils are very aromatic and fresh, so we add them. We've also used
sticky traps.