Whilst sorting out stuff for the cake shop & having some odd tv show in the background I overheard the best solution for preventing moths & their little critter of eggs ruining your cashmere... First, they hate Cedar - so spray some oil onto a piece of kitchen towel (or equivalent) and pierce a little hole so that it pops over your hanger, and hang one pieces on every 5/6 hangers which should keep those little buggers away.
If your wardrobe is rammed like sardines full of wool, cashmere etc... it's more than likely that your cashmere has moth eggs - yuck-o-rama!
How to get rid???
Chuck your cashmere into a frozen zip lock/see through plastic bag - make sure it's sealed and place in your freezer, yup FREEZER over night. This will kill the eggs for sure.
BTW the eggs are so tiny, they're not visible to the eye...
So there you have it!