|Do you have a clean room setup in your basement? Did you suit-up & glove-up before working on them, like THS?|
Here's why it can't be done in a non-clean room >> Notice the gap between the read/write head compared to the Platter Contaminants.
In other words, you destroyed the hard drive(s) the minute you opened the cases. You might be able to retrieve your files by taking the parts to a data recovery service, but I'm guessing it would cost a small fortune.