The sweet smell of yeast attracts slugs to beer like moths to a flame. (And often it’s in a Solo cup that they meet their boozy demise.) “A lot of slug species feed on decaying plant material,” says Ian Bedford, head of the John Innes Centre’s Entomology Facility in the U.K. Beer resembles overripe fruits, which burst with naturally fermenting yeasts that slugs can’t resist. If you need to clear your garden of pests but can’t bear to waste some suds, try this substitute: Mix a packet of dry yeast with two tablespoons of flour, two cups of warm water, and a spoonful of sugar to make the slug medicine go down.

This story originally appeared in the September 2014 issue of mental_floss magazine. Subscribe to our print edition here, and our iPad edition here.