Commercial cucumbers are coated in a food-grade petroleum-based wax to prevent moisture loss. This wax doesn't just sit on top; it acts as a solvent that "locks" pesticides into the skin of the vegetable.

 No amount of scrubbing or vinegar-soaking can remove what's trapped under the wax. Unless you’re buying organic or home-grown, peeling the cucumber is the only way to reduce your pesticide exposure by up to 80%.