Murphy’s Oil soap is an oil-based polish. It leaves OIL on the floor (the water evaporates… the soap and oil residue do NOT).
This oil will penetrate THROUGH the floor’s polyurethane finish and onto/into the wood.
Murphy’s Oil Soap is a contaminant… Think of it just like a gallon of cooking oil that has been left to soak into the wood. The hardwood grabs the oil and holds onto it. When you try to get a new finish (polyurethane) to grab the wood, it simply can’t… because the oil prevents the polyurethane from properly adhering.
Now you have what is known as a chemical adhesion failure.
