Prepare your fruit roll up mixture and pour in a wax paper lined cookie sheet. Put cheesecloth over the pan (not touching) to keep bugs off. For veggies and fruit, put sliced pieces on a cooling rack in a baking pan and cover with cheesecloth.
Put food in back window in the sun. Leave window cracked to let moisture out.
Thin sliced fruit and fruit leather should dry in about 6 hours of hot sun in the car. Large pieces (like half of an apricot) could take up to 2 days.