Don't think so, mimeograph stencils are typed or drawn on with a stylus so that pressure pushes aside the wax layer and leaves the underlying thin fabric expose

Don't think so, mimeograph stencils are typed or drawn on with a stylus so that pressure pushes aside the wax layer and leaves the underlying thin fabric exposed. Then the stencil goes into the mimeograph to make hundreds or thousands of copies. Ink, usually black, did not fade. There were ancient photocopying processes, including wet ones where individual sheets were hung to dry like laundry. Plus the famous 'blueprints', which were used for large engineering drawings. Maybe your copies are some variation of those, but by the late 80s pretty much everything for regular sized photocopies was dry process with black toner, like we use today minus the digital controllers.