I have had some moldy cuttings when rooting in the bag. The cuttings had been scrubbed with soap and sprayed with 10% bleach before going into the bag. When they became moldy, if roots hadn't formed, I took them out, cleaned them with soap and water and 10% bleach, discarded the paper wrapper and rewrapped. I had more problem with paper towels than newspaper and generally, if there was mold, the paper was too wet or I had not been opening the bag enough to exchange air. Now I leave the bags open for a day or two to get humidity levels right before I close them and make it a point to air them out every day or two. Some formerly "furry" cuttings are now happily growing roots and leaves, some aren't.