Wanting to know if rust neutralizer is needed for very light surface rust. I am going to undercoat and paint under my 89 gt. The car has 53K and the undercarriage is clean but has some minor surface rust that I can knock down with a wire brush. Also have welded subframe cons. that have been painted but I want to coat them and everything else under the car I can reach. Bought some Loctite Extend Rust Neutralizer thinking I would hit any wire brushed areas prior to the undercoating. Anyone have any thoughts or suggestions?