Patience is the key, but in addition to the above I have used a long hand sewing needle to carefully pic out wound up thread.
And if you can't get it out this way, go here: {
http://thefeatherweight221factory.com/page10.php } for instructions to take the bobbin assembly apart just far enough to clear the thread jam. Look down at the big red arrow on the bottom and click on the thread jam link.
Joe