whether to clean this leather

So I'm cleaning a house for a decorater who's clients are away.Its pretty much all flooring and all the upholstered furniture they own. I'm done with everything but a leather ottoman, chair and couch. The chair and ottoman seem to be part of a set. On the label for the ottoman it state that due to it being made of a natural leather it cannot be cleaned. SO DOES THAT MEAN IT REALLY CAN'T? They are both very worn and the ottoman is heavily soiled.The sofa is a baker leather sofa. I called Baker...

whether to clean this leather