Here are some of my recent discoveries ( not really recent, nor that much of a discovery, but found the following useful when I was stuck)
- Screwdriver shaft to access terminal when boosting a car
- Melting a glue stick with a lighter
- Wine cork as a floater for fishing
- Acetone or ATF and mineral oil as penetrating oil
- A tailor's hold pin with a broken tip to change watch bracelet links
- Towels or newspaper wrapped around a large pot/bottle to maintain a temperature ( dyes, mash for homebrewing, keeping food warm )
- A fine cotton cloth and a wire hoop for an excellent sieve (malted barley, coffee, soy drink, almond drink etc.)
- Linseed oil and turpentine for sealing and polishing wood