Hi S.---Go to any hardware store or to Home Depot, etc and you can get traps. Pantry moths love grains, nuts and seeds. I have them in my birdfood. I've got the traps away from the birdseed so as not to attract them to the area I want to keep them from. The traps are located across the garage from the seed..
They did, most likely, come in with the corn litter. The natural litter was a great idea, but it sounds like an impractical one. Good luck. D.