Do your door,boot and bonnet jams with waterless polish. Spray it on and brush it in and wipe off and all the muck comes with it and leaves a polished surface so water runs away easily. Engine bay. If its mainly dry dust etc. use a paint brush (1", 2") and a flexible hose on the vacuum to lift every thing off and then brush on / wipe on "Armorall" satin black and it comes up lovely without looking at all 'blingy'. Black shoe polish on the tyres.