To the best of my knowledge, there are no "metal primers" in dip, nor do they react with iron oxide. Dip is simply a surface sealer, similar to paint. Excepting that dip hardens through evaporation where paint hardens through a chemical reaction.
And, to the best of my knowledge, cleaning the traps or rusting them will have no effect on whether or not your finished traps are sticky. These are dilution and solvent problems. I use lantern fuel (naphtha, white gas) diluted to the manufacturer's recommendation. Using less solvent is not better.
That said, rust will give "tooth" to the surface of the metal, and the dip will form a better physical bond. But, I haven't purposefully rusted any traps that I intended to dip in over 20 years. The dip has pretty good adhesion as is. But as previously mentioned, I did decide it was better to clean the factory oils off them.
Hal
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Endeavor to persevere.