Hi Mandy,
I don't know exactly what green mint oil is, maybe oil from fresh mint leaves? Regardless, I do know peppermint oil from distillation extraction, deters rodents and many types of insects. So that might also keep those pesky mice and other bugs from nibbling on your potatoes during storage. Although I'm not sure how well peppermint-potatoes will tast for dinner, so you could always use the peppermint oil to treat the perimeter and floors, of your
root celler, to deter those pests from coming in and nibbling.
I hope that helps!