What are your mold remediation horror stories?

[Drew Clayton]

I'm considering buying an off-market home from an acquaintance, but it's a hoarding situation that reportedly (I haven't been inside for obvious reasons) has mold running up a wall. For extensive mold remediation situations like this, do they really get it all out, or is there risk that it could return or make future tenants/buyers sick? How has it gone right or wrong for you?