under seal?

At some point in the future dunno when but hay Lol.... I'm gonna take the bumpers off the car give it all a good clean up behind them on the chassis but then what wud I use on them.. Under seal? Or is that more for the wheel arch area.. Not really sure as never done it as yet

As a dressing I'd use chemical guys bare bones on the wheel arches etc need to wear gloves with it because its a nightmare to get off your hands, chemical guys jetseal is also recommended