Common opening tool, is common for a locksmith, a coat hanger may work
but wouldn't count on it, as it's probably not strong enough.
My common opening tools are 4-5mm (5/32-3/16 in)thick, they can be bent
somewhat to allow reshaping of the tool for certain cars, but don't bend
as easily as a coat hanger.

Crude ascii drawing of common opening tool(s)

  --                     --
 |                         |
 |                         |
  --------------------      --------------------
                      |                         |
                     --                          --

Two tools, one has a inward hook, the other has a outward hook at the
end, and there's a larger  and smaller end, the hook is the same size
just the  right angle bend is a different size.
if you bent a hanger into a similar shape with a right angle it may work
but you also may not have enough strength in the hanger to do the job.