How much concrete?
first sray with a Hotsy, with a good angle not perpendicular to surface, any clumps the size of a dime or larger give the ballpeen treatment, gently, very gently if you dont want to damage the paint, the more concrete,more patience, methodically work every part of concrete, rinseoff chippings. muriatic acid works well to remove the concrete, Be Cautious it will etch aluminum, may fade plastics color, may etch cheap chrome, glass, any rust or bare metal. DO NOT let it even drip on your radiator! Dilute the acid with water. 10% acid /90% water. Plan on a couple 2-3 applications or more. start with a weak acid solute(depending how much concrete splatter) and add more acid if necessary(acid20%-30%+) , Always try in an inconspicuos-non visable place, rinse and allow to dry before checking for damage.spray application is best. do not allow solution to dry on the vehicle(keep it moving), apply several times, then remove using a medium stiffness brush, dipping in the solution often (to remove concretechips from brush) brushing only the affected area,spray with Hotsy, repeat. wear safety glasses and vynl gloves