My Mom always left the peels on. Mashed them up....peel and all....and they were sooo good! After I got married I was told "my mother doesn't cook them that way" and things changed..... Now, due to physical challenges I usually buy the pre-mashed frozen potatoes. Next time I go to the grocery I'm buying a big ole' bag of potatoes, boiling them with the skins on and mashing them up just like my Mom did. Really....it's the only way!