i have not tryed this yet but i have been told that sail cleaner like for sail boats will work quite well. i am going ot try it, i just haven't gone to the boat and marine store to get some yet. i would try that.
Here is a keew idea after washing the top..Since my top was sprayed with some sort of protectant with my Permaplate warranty ( It was some sort of white powder that the dealer sprayed it with), i figured the Zip WAx brand made by turtle wax is the best car washing liquid around! Anyways, after I wash my whole entire car (top to bottom) I let the top dry and use a lint brush to clean up the residue from the top..Looks way clean!!