Try a circular wire brush in an electric drill. It quickly strips away much of the old glue, but in doing so scatters lots of little bits around the area. It helps to have a vacuum cleaner in the vicinity and don't forget to wear a dust mask. This method will expose enough surface to apply fresh adhesive to stick on a new covering. however, it leaves old glue in the little hollows in the woven glass hull surface so may not be sufficient for painting. Good luck with the job. Nigel.