Do mothballs get rid of roaches?

Mothballs don't deter snakes directly. they may keep away mice and other rodents that the snake eats. If there is no food for the snakes, then the snakes wont hang around your house.

I have heard that if you pour kerosene around your yard, they wont cross it because it burns or irritates their skin. Never tryed it but it's something to keep in mind.