User blog comment:FairyRaven/Fairy Tail vs. Alvarez Empire! Place your bets!/@comment-7418318-20150915202219/@comment-7418318-20150917074449

Sure Gajeel's Iron/Steele skin is unlikely to be completely immune, but then I never claimed it was. I just said it'd be useful and I think it is. Even though the sand is likely able to corrode the metal, it'll still take a whole lot longer than stipping away skin would.