So it really should be "Tight Rivets"!
How about plain old dioctyl sodium sulfosuccinate. I.E.: DOSS, Colace, or generic equivalent thereof. You want to soften those rivets, not blast them!
For many years, after repairing ladies' posteriors following difficult childbirth, I didn't want my repair to "pull out" so to speak. Instructions were Colace 100 mg and Milk of Magnesia 30cc, twice daily for 10 days whether needed or not.
Trust me, they were all loose!
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Graham