The problem is with that, from many years of experience, its a waste of your time as bad credit people generally won't invest the time, effort and costs required to fix their lives.
They expect it to be free or they think they can write letters to the credit bureaus and fix their issues on their own. We in the know...know those letters go right into the garbage when the 3 reporting agencies receive them!
Here' a simple test:
Ask them to take $500.00 and open a secured credit card at a Bank. I believe you'll find that 99% of them won't even complete such a basic first step to help their selves re-establish credit.