As it happens, the U.S. Dept. of Defense lists several ways to reliably and effectively decommission a disk and using a sledgehammer happens to be one of them. (Seriously.) That method is used when you have a disk that used to contain Sensitive or Secret data and you want to assure that its content never falls into foreign hands. It is approved because not everyone has the modified wood-chipper needed to tear a drive apart and shred it.
Have to admit the bleach was an interesting touch. If the drive case was cracked and bleach got into it, the drive motor will be shot and useless but I'm not sure that the drive surface coating is affected by bleach. I think that is usually alkaline but modern drive coatings are more likely to be affected by acid.
Drive repair at that level is probably not possible even with big bucks. I've seen how hard it is to recover data from a scratched drive. From a crushed one? Sheesh!