OP your last post and your first post are very different. The danger of open forms are they are open anyone can read things and out of desperation try them. It is certainly bad judgment on the readers part but still we as a community must be aware of this. yours is the first time I have heard a vet suggest such a thing it has been a 'home cure thing' kicked around the internet for years.

The issue is using a known toxin to treat a health issue is a serious deal. I am exceptionally surprised a vet would ever suggest using a toxin this way as there is little data.

How much will cause long term effects?
How much is a correct dose?
What the full systemic effects of phenols are on reptiles?

All of these are unknown. In Canada a vet could very easily lose his or her licence for using a treatment that is un tested with a chemical (make no mistake in thinking essential oils are not chemicals) There are so many questions with no answers around phenols.

Most believe that the small amount of phenolic compounds in cedar wood is harmful, the even smaller amount found in pine is hotly debated.

You are suggesting using euctynol a phenol in a bottle and Vicks made from cedar leaves and carbomer. Over exposure could easily cause long term damage to lungs, liver, and skin. The method you describe is contrary to Vicks instructions on not heating it and not allowing it into the mucus membranes of the lungs and nostrils. this has all the ear marks of a home cure and none of a safe practice. I would get a new vet yours is using your animals as an experiment. personally I would report your vet to the CVMA.

You see the issue there are far to many questions with no answers. It cannot be claimed 'safe' until the full effects of phenol compounds are studied. I do not know of any studies even have been started. They are simply a big unknown and it is all guess work there are other methods that are known to work with far far less risk associated with them.