Stoner's Tarminator too. AG does sell that. It will remove very hard old sap. Just build a little dam around the sap with a towel; let it soak; wipe it off. It may take a couple of apps. I've had good luck with it.
does'nt gojo contain pumice abrasives in it? if so i wouldnt use that on paint....but if i can remember correct they make 2 types of gojo one with the abrasive stuff and one without. anyways just get some 98% pure d-limonine its whats in nearly all "citrus" cleaners. the pure oil will work tons better then any cleaner i bet..just wear some gloves if you have sensitive hands(d-limonine makes my finger tips feel like there a bit hot) AG needs to carry pure d-limonene its expensive but it does work