I know salt will kill slugs i have used that in the past.
I did some googleing around and didn't find any reference to salt killing moths...
We usually think of moths eating holes in clothing, blankets, or rugs, but they will also damage upholstery, piano felt, and even natural bristle brushes. Although moths do eat fabric materials, it’s not the fabric itself they are primarily attracted to: it’s the dirt, lint, salt, dead insects, or stains from human sweat and food such as tomato juice, milk, coffee, and beef gravy that moths like to eat.
But it seams some are attracted to salt. You might want to test this first or you may end up with more moths then you know what to do with.