Hi all got new bunk board brackets my issue is now a even harder one! My bolts are rusted stuck! Have soaked with penetrating oil bolts and nuts are starting to round off! What best way to remove at least ten bolts( replacing all brackets) and nuts? Grinding off? Drilling out? Cutting torch! Need any advice as to maintain the welded integrity of the brace it's bolted too! It's 98 stratos trail trailer.