If the glue IS water soluable maybe you could disolve it from the bottom up.

#2 Pen eraser might work also.

#3 very fine sandpaper to start with and work from there.

for $10 if you ruin it it's not like you won't be able to make your mortgage payment.

Of course if you can fix it maybe it is your mortgage paymant.

P.S. I know someone that can use a good image of that. HAR HAR HAR