I’m making candied fruit and I need somewhere nonstick to place them while they cool, but I don’t have parchment paper. I don’t know how much the sugar will stick to aluminum.
Aluminum foil is not non-stick, except for those specially silicone or otherwise coated foils that are explicitly marketed as such. (And which are probably even more of an environmental nightmare than regular foil, but I digress.)
If you see aluminum foil used in a candy making context, you will notice that they recommend greasing or oiling the foil before pouring or placing the sugary food on it. Personally, I’ve had mixed results, you really have to grease the foil well. If a bit of fat or oil is ok for you, you can use aluminum foil, otherwise I recommend either a shopping trip or checking your household for alternatives.
For your special case of candied fruit, you want the sugar syrup to drip off, not the fruit to sit in a puddle. Have you got a cooling rack at hand? Use it, ideally with a tray underneath to catch the drippings and make cleaning easy. The significantly smaller area of contact will reduce sticking, especially if you move the fruit a few times before they dry fully.
You can use non-stick aluminum foil, no greasing required. It's widely available in the food wrap section of any grocer.
One brand is Reynolds: http://www.reynoldskitchens.com/aluminum-foil/non-stick-foil/