How do i get rid of pantry moths properly?

The reason it takes three afternoons is they come back. Empty the whole cupboard and bin anything open that's got webbing or clumps in it - flour, oats, rice, nuts, bird seed and pet food are the usual culprits. Hoover everything, including the shelf holes and the corners where the worktop meets the unit, the eggs and cocoons hide in those cracks. Wipe down with soapy water. Then keep dry goods in sealed jars or tubs for a good while after. A pheromone trap tells you if any are still around.