the saddest thing is that with your car yes you need salt so you dont get suck. with your jeep you dont get stuck.
but back to the right topic. i normally use the car wash by my house that has an under carriage sprayer after i go and hose it down with the power washer. it cost about 10 bucks 1 to 2 times a week but if it makes my jeep survive the rust for a little longer its all worth it