Dealing with Underwater Notes

[Sean M.]

So I've got a good handle on non-performing notes (2nds) that are both totally and partially covered by remaining equity in the house.   Does anyone deal with or know the approaches for no equity 2nds?  Seems like a great way to get wiped out, but I know PPR and some of the other funds are buying huge pools that include lots of these, so there must be a value to them (I guess at the right price, anything becomes profitable). I'd love to add and @Dave Van Horn and @Dion DePaoli, but I'm new and haven't figured that out yet. 

Thanks in advance.