Consider the following excerpt discussing three techniques for restoring historic iron structures:
"Conservators assessing historic cast-iron bridges face competing restoration paradigms. The traditional practice of sandblasting surface rust achieves immediate aesthetic clarity, yet it irresponsibly strips the protective oxide patina and accelerates structural decay. In contrast, chemical chelation treatments show genuine promise by selectively binding iron corrosion products without disturbing sound metal, though their prohibitive cost currently restricts widespread deployment. Finally, microbial bio-cleaning—which utilizes harmless anaerobic bacteria to consume sulfur crusts—represents an impeccably elegant, fully sustainable breakthrough that deserves immediate, universal adoption across all municipal heritage projects."
Match each restoration method mentioned in the passage with the phrase that most accurately reflects the author's attitude toward that method.
- Traditional sandblastingExplicit disapproval due to underlying structural risks
- Chemical chelation treatmentsQualified approval tempered by practical financial limitations
- Microbial bio-cleaningUnreserved advocacy based on technical and environmental merit