My 2 cents, If the fastener just turns hard but will move then just about anything oil-ish will work to make it come off smoother.
If it's seized or heavily rusted then the only real solution is the blue wrench (torch).
As far as assembling parts parts that would be expected to rust and be hard to get back off I just use anti seize.
If it's seized or heavily rusted then the only real solution is the blue wrench (torch).
As far as assembling parts parts that would be expected to rust and be hard to get back off I just use anti seize.

