Take a paper clip and use the pliers on your multitool to cut the longest straight section. Quickly run a knife blade down that section of the paper clip. Make sure you go the same direction each time for at least 50 to 100 times. This will magnify the paper clip's "north" end.
Fill a small, non-magnetic cup with some water. Place a leaf with the paper clip segment on it into the middle of the water. Wait for a couple of seconds until the paper clip points north.
How to make fishing hooks out of paper clips
When SHTF, you can turn also paper clips into DIY fishing hooks. Note that as a makeshift hook, paper clips will only catch small fish due to how easily they bend.
You will need:
String or fishing line
To make a hook, straighten a paper clip and leave one "J" bend in place.
Make a small loop on the other end for the string. Reinforce the string loop by wrapping the remainder of the paper clip around the hook twice. Trim what's left over with a multitool.
Paper clips are shiny and you can use extra paper clips as fishing lures.