I recommend using a serrated peeler because it grabs the edges of the peach skin beautifully. Ripe peaches are also easier to peel so look for firm yet ripe peaches to use in this peach crisp. Once you get a corner pulled up, it easily separates from the rest of the fruit. Some people blanch their peaches in hot water, like you do for tomatoes, to help remove the peel. Choose whichever method works better for you.