For all purpose penetrant, lube, and protection...

JB-80 by Justice Brothers

Once you break the bolt loose you need to lube it while unscrewing it or it could break on the way out. Also works great for lubing any metal to metal sliding surfaces and resists water washing it away. In my old job I sold it to huge gate company and their customers would call and Demand JB-80 to maintain their gates

For years we also sold it to many Chrysler dealerships that could have just asked for the Mopar stuff that was also on the shelf.