Hi,
I haven't tried it myself, but I have a video from the Sailrite company that shows how they remove adhesive residue from sails. They use a product called "Goo Gone". They soak the area, cover it with a cloth or paper towel and soak that also. After it sits for a while (you'll have to experiment to see how long), the gunk will wipe off and roll up. A second application is needed sometimes.
Good luck,
Jack Hoying
Fort Loramie, Ohio
Prindle 18 #1645
http://www.bright.net/~jmhoying/sailing/prindle.htm