Thymol is not approved for use in U.S. Please don't use unapproved
substances! I have encountered it and I can concur that it has a very vile
odor, not like garden thyme at all. I am not surprised to hear that it would
linger in hives. Wax absorbs readily odors.

We have had good luck rotating apistan and coumaphos. I would like to
substitute formic acid for coumaphos, but I don't know if it is readily
available yet. It tends to eat up the packaging. Formic is very acidic and
has an acrid odor, but evidently it doesn't taint honey.

PB