Do these Strip Discs really not damage the surface underneath the rust/paint?

Yes, with Clean & Strip Discs you can thoroughly remove paint and rust without damaging the original surface. Because of its unique open structure, the Clean & Strip only removes the upper layer of the object, without grinding or cutting into the surface. The discs are used for cleaning surfaces, removing layers of paint and epoxy, preparing surfaces which need to be painted or coated in hard-to-reach places.