I like rem oil in the spray can. It leaves a fine film when it dries but isnt a dirt attractor. I have used break free in the can also with good results. I just dont care for the smell of it. The best thing to do is to find an old piece of metal and degrease the whole thing then mark off sections with a black permanent marker. Number the sections and write down on paper the corresponding oil. Try to find something that doesnt have rust already on it. Next treat each section with some popular gun oils and leave it outside for awhile in the rain and such. Make sure you put the same amount on each section. Go back and see which part started rusting first, the second, and so on. Make sure to check it each day for best results. Some salt water can show you what protects best too.