How to clean cardboard type layer off subfloor
We have removed the asbestos layers off our 1915 year old fir floor and now have this kind of cardboard looking layer left that is adhered to the fir subloor. Note: we had the floor layers tested and the asbestos culprits was sandwiched between other layers so we are not dealing with asbestos in this final layer.
How do we safely remove it?
I've heard of pouring water on the subfloor to loosen the adhesive, but we don't want to introduce too much water into the insulation below.