Ah, the good old days . . .
When such as Carbona, CarbonTet, and TCE were available to the public . . . and let's not forget Freon R-12 at 99 cents a can at K-Mart! ? But I digress . . .
I usually take a bit of Dawn and mix it with commercial tar and bug remover (but I bet mineral spirits would work too). ?On paint, a soft cloth does the trick, on textured plastic (i.e. cladding, etc.) a soft toothbrush works well. ?The soap seems to keep the solvent in place so as to keep it from running off as easily.
Followup with a re-wash to get rid of the oily solvent, and then either wax paint or put protectant on the plastic.