as with all detailing/correction, use the least invasive method possible. So, in that order...
- try hot water (use a towel to let is steep for a few minutes)
- Avon S.O.S
- WD40
- Bug/Remover
- Denatured alcohol (if it's really stubborn and baked rock hard)
Once it's all removed, you'll need to re-protect the finish w/ some fresh wax.
Good luck