Have you tried the mixture of:
1 part sugar
1 part corn meal
2 parts boric acid powder
Mix together and store in jar.
Put a small amount in a soda bottle cap and place in an area near their nest if you know where it is, but out of the way of any of your pets.
My mother would put it in cabinets, the pantry and even the window sill where it seemed they gained entry.
I know - I can hear the concerns regarding the boric acid powder, and as long as it's used carefully regarding pets and little people, we've never had a problem. It also works great on roaches...and Mom lived in Hawaii!