Neither ants nor snails are fans of used coffee grounds. Simply sprinkle the grounds to form a barrier to dissuade ants from crossing certain point, or cover an ant hill with grounds to persuade them to move on. Snails are not fans of the acidic nature of coffee nor the scent, so scattering them in key places will make them think twice about nibbling on your prize plants.
Disclaimer: Puro will not be held accountable for any used coffee mishaps. Please check with your local pest control company and gardener before application.
Learn about other uses for used coffee grounds.