Automobile Enthusiasts

The área around the dried with water then put concentrated bug and tar remover on a cloth and rub onto the dried sap area. Let it soak in for a day or two. Whittle the non-bristle end of a toothbrush to a flat screwdriver shape. Use the toothbrush to flake away at the dried sap. Reapply and soak in tar remover as needed. Repeat. When things get towards the end, use tar remover on a sponge. Wrap a plastic potato sack around the sponge. The sack makes it abrasive enough to loosen the sap.

Hope this helps. Don't know about the softtop...I would ask a local sports car club.
My sister got a DUI and did not drive her car for a year. I cleaned off the tree sap for her.