The pinhole in the "What's This" No. 360 reminded me of this tip.
Metal content: Reading a mike, the markings on a small drill bit, or a phone number printed on a tool supplier's business card......when you haven't got your reading glasses with you......and nobody is around to ask for help.
Use a "hand made" pinhole lens.
Cup your hand slightly and cross your thumb over your index finger. Roll and squeeze your thumb sideways until you can see light coming through a little opening (about .015" diameter) between your thumb and the place where your forefinger joins your hand.
Freeze your fingers in that position, bring your hand up to your eye and peer through that "pinhole". Put the thing you need to read about two inches in front of your hand and alter that distance until it's in focus.
Presto! Not much depth of field or angle of view, but if you only need to read a few characters it's much better than nothing.
I've always wondered how many millennia ago some poor bugger with deteriorating eyesight discovered that trick, using nothing other than the hand G-d gave him.