A soft detail brush or even an old toothbrush.Make sure it's not stiff bristled or you're liable to scratch paint.Use the brush and a moderate to full strength solution of simple green then wipe off with a soft cloth.
Is it newer paint or original factory? Does color come off when you wax or buff it? If it's the type of paint that doesn't have a clear coat over it,then you may be able to get away with wet sanding the orange peel area.Do this to smooth out the orange peel so there's less of it or none at all.If it's clear coated,I probably wouldn't wet sand it as you dont know just how much clear finish is left.