:Hi Bert, yes a paper cone can be repaired with some tissue paper and use some white elmers glue ever so slighly diluted with water, you place a piece of tissue paper slightly wider than the tear and with a soft brush or q-tip dab the glue on the tissue paper to soak tru make sure that tear in cone is tight might even have to use some tape on the underside depending on how resilient the tear is, and let dry, should be good as new.
A lot of people also use tea bag paper, it's more fibrous and holds up better than tissue paper.