The clutch is probably slipping as the surface to t that it 's glued to has lost it stick um or the clutch mateial has deteriorated.
A couple of differant ways to approach it;
The lazy man'sw ay is to put a couple of small pieces of sandpaper between the clutch and drive.
Another method is get an old tube from a tire and cut a snall cirle out of it,. Cut a hole to fit around the drive with a slit and glue it. Keep them apart while the glue is drying and remove the old clutch material.
Bill N