He was (a) factually wrong:
https://www.factcheck.org/2016/09/tr...id-wash-facts/
And (b) it is by no means clear that he didn't literally mean dipping the hard drive in acid. He consistently used the wrong words (who uses "acid wash" for wiping a hard drive? As opposed to say, jeans). This is the same man who claimed Obama "tapped his phones" (sic). It's entirely believable that he's such a dinosaur that he actually thought it was literally bleach or acid.