I've never really thought about it. Pull really hard and hope you don't loose 1/2 a spool of braid in one hit?

But seriously. Have you tried a bow and arrow release? If it's not completely driven in there, it'll help pop out alot of snags. I'd try that or moving down the shore and changing the angle to get it out that way. Lastly, I'd try a direct pull and hope the jig would pop out or the line breaks at the knot without loosing too much.