“Prep” vs “wipe”

I think we can infer that “wiping” Bucky meant wiping his memories using horrific electric shock therapy, etc, but what does “prepping” him entail? And why does his time out of cryofreeze affect it?

I think we can infer that “wiping” Bucky meant wiping his memories using horrific electric shock therapy, etc, but what does “prepping” him entail? And why does his time out of cryofreeze affect it?