Best method/detergent to remove sap?

[area53 at validpath.com (Jeff Toomasson)]

While my project car has been in the shop, my other mk1 has been languishing 
under a tree for the last couple of months because I've been using the driveway 
for woodworking. I hadn't really been driving it because it has a bad oil 
temperature problem (cause as of yet unknown). Needless to say I should be shot 
for letting it get this dirty, but what can I use to get the sap off without 
scrubbing the $hit out of it and screwing up the paint?

Thanks!

JT