Leo, while I do not have any feedback specifically with those two products, there are two basic types of acids. One in heavy concentrate attacks organic things (typically Caustic) which are paint, plastic, bakelite, clotch, grease, etc. however it will do very little for removing rust. Phosphoric & Muratic on the other hand generally will do little against organic items however they do attack iron oxides (rust). These are generalizations and you will need to study up on the effects of both crystals and how to use them however the reason I say this is to find out the ingredients of either of the products you mentioned and you will see what your next plan is.
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