I've used vinegar tilled into the soil to remove the bonding that keeps it sticky.
http://www.minsocam.org/ammin/AM56/AM56_1082.pdf
This article has other sugestions that probably work better. which I assume if you get a pound of the glacial citric acid you could mix it into a few gallons then agitate with tiller to get it to "free up"
Gaston