If its bugs just wet soft teeshirt and lay it on tank for a bit and it will come right off. I have only used water for my whole bike and it works great and easy. Cheap also!
I do a wheel spray on wheels.
Been using the Harley denim cleaner, works a little better than the ammonia free windex. After this bottle is gone I'll go back to the windex for the cost if I have to use a little more it is no biggy.