I tried a product couple years ago called u s a fluid, the vendor is at speed week. seems to work well. I dilute it with mineral spirits , and use a garden sprayer to drench underneath vehicle and trailer. salt still sticks a bit , but falls right off. when I get home , I park both in the driveway and put sprinklers underneath em , and let it rinse all day . salt seems to be all gone. I then spray salt x over everything. I do live in a rural area and have a long gravel driveway and use well water. the deer and raccoons love licking the driveway