Beeswax has been used for securing the windings on toroids.

According to my boss in the late '60s and
early '70s,W.T.G. Glasspool (would you
guess he was British?), beeswax was widely
used in the past to secure coil windings,
seal slugs in the cores of forms and
transformers, etc.. Apparently it doesn't
reduce the "Q" too much, and was readily
available in those days.

73, John - K6QQ