After leaving the varroa inspections boards in for 96 hours I checked to see the results of the treatment.  The first hive had a huge mite drop, this is the hive I treated using a homemade thymol treatment. I think it is safe to say it didn’t work.

The second hive had no mites on the inspection board.

The third hive had about 20 mites.

Checking varroa inspection boards