Leaving the skin on can add a rustic and earthy flavor to the dish, as well as provide extra texture and nutritional benefits. If you leave the skin on then here are some tips to help you with the process: 1. Yukon Gold or red potatoes, have a thinner and more flavorful skins when compared to the russet variety. 2. Thoroughly wash and scrub the potatoes to remove any dirt or debris from the skins. 3. Use a potato masher or electric mixer when mashing with skin. Using a potato ricer may not be the best choice, as the skin could potentially obstruct the small holes in the ricer.