Block the glare
Make glacier goggles to prevent snow blindness. Fold foil into a 6-by-2-inch bar and mold the mask to your face. Cut a space for your nose and horizontal slits for your eyes. Fold foil over at the edges to reinforce before poking holes for a cordage head strap.
Splint a joint
Wrap a broken finger in cloth, then fold several layers of foil into a bar twice the length of your finger. Fold it in half longways over your finger to create a two-sided splint. (It’s stronger than it looks.) Bend the splint to hold the finger at the most comfortable angle.
Signal for help
Wrap foil around a plate or a square frame made of twigs and reflect sunlight to signal aircraft. (Smooth out creases for best results). Too busy working that survival grind? Make sure your signal is always on: Tie ribbons of foil to trees or bushes in open areas.
Leave a trail
Lost at night? As you hike, wrap foil around trailside vegetation to catch your headlamp beam, so you can retrace your steps.
Fashion a cup to hold water for boiling. Suspend it over coals (foil will melt in a direct flame).
Waterproof your phone
Don’t have a plastic bag? Wrap electronics in foil to protect them from heavy rain. Fold the edges over several times and crimp tightly to seal.