Ask yourself: Am I ready to be a bottom feeder on the lowest rung of society, rifling through garbage in the hopes of squeezing some poor schlub out of a few bucks?
I’m tempted to do this, just to then turn around and send a letter to the debtors saying that I will take no attempts to collect this debt and you do not need to pay.
There is a church doing exactly that with medical debt:
As noted, there are some orgs trying to actually discharge debts this way. You should try hooking up with one of them, they probably know what they legal/administrative tasks to do it are.