That would be an excellent application for the product. If it is just light surface rust, it could just come off with one application of Fluid Film. As far as road spray and salt, Fluid Film creates a barrier that cuts off oxygen, keeping metals corrosion free. If you want to hose off the surface after treating with Fluid Film, just don't power wash. A regular hose wash at about 30psi won't have enough pressure to remove the product, just whatever grime or salt is sticking.
It's hard to give an estimate on when to reapply. You will know it is time when there is no longer a shine to the surface. Let me put it this way: If you were to coat a plow and just leave it indoors, the product could still be there three years later. If you were to coat a plow and leave it sitting outdoors in full exposure, Fluid Film would last from two to three months. Once you are actively engaged, it is hard to say because of environmental conditions and time of use.
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