Get a can making sure it is clean and dry

Cut the top and bottom off

Cut straight down so you can lay it out flat

Cut so that there is a nice edge

Fold one side into the middle

Next cut a piece of wire about 1/2 shorter that each side and carefully stick the wire in the middle with a bit of tape

Fold the edges up.

Then fold the last bit over

Now spend a little while bending it to the shape of your wrist.
Now run along to make you can cuff