You can soak it in rubbing alcohol multiple times. This will take a while because you're only going to take the sap off layer by miniscule layer. Once you've got it nearly gone you should be able to wipe it off with a good detail spray. Make sure you re-wax the entire area around it where the alcohol touched the paint.
If you want to clay bar the entire car that should work to but even a claybar may have some problems pulling that up. And I don't like using an entire claybar or even half a bar on one spot. Besides, you really want to loosen the bond it has formed with your paint. A strong clay bar might just rip it right off the paint but what's stuck to the bottom of the sap that might be coming off with it?