Use cookie sheets with edges (13" X 15" or 12" X 17" pans work well). Line with plastic wrap, being careful to smooth out the wrinkles, or spray with vegetable oil cooking spray. Do not use waxed paper or aluminum foil.
Fruit leathers can be poured into a single large sheet or into several smaller sizes along the cookie sheet. Avoid pouring purée too close to the edge of the cookie sheet.
Set oven at the lowest setting, which should be 175 *F. If your oven does n If your oven does not a setting this low, it may not be suitable for home drying of foods.
Place the cookie sheets with purée on oven racks. Leave the oven door open about 2 to 6 inches. Check oven temperature periodically with a thermometer to keep the air temperature at about 175*F.
If the temperature gets too high, the oven may have to be temporarily turned off, and then turned on again.
Drying time will be longer for the large leather than smaller ones. Drying time may also be longer in a regular oven than in an electric dehydrator, depending on temperature control during drying. For a large leather, begin checking your leather at 8 to 10 hours.