Hey TCL...
Figured this was gonna get lost in the OT thread... So i figured I would go ahead and barge in over here as well...
For the record, just found out my mother used it. not really sure if it helped or not. I wish I could have seen her face when I asked her - Hey ma, do you use vaseline for lube...........ing your chickens combs?
Not sure about your coop or your design, but... I try to do my best to not place bandaids on problems, as nothing is really solved (or at least there is a higher chance of not being solved)
I would look at trying to fix the why. Meaning to look at what can be done to the stop the problem, instead of just protecting the comb. There may be something lurking in the background.
Not enough ventilation?
Can't really have to much, but to much ventilation?
Bird health?
Air quality in the coop?
Feeding habits?
Any others birds with the same problem?
Roosting space?
Poo (deep liter method or some other method)?
Birds being disturbed? (predation, traffic, etc.)
Lighting outside?
What was the weather like? calm, high humidity, high winds, etc.
Have you changed anything inside or outside the coop?
Does anything need to be changed? (summer ventilation is different than winter - I found out the hard way)
What new problems will new changes create?
Any new birds?
What or how can you do to change your thought processes to ensure similar situations don't occur in the future? (why is your coop designed the way it is, why did you choose that design, what would you do different and why, why are the birds the breed they are, why did I provide a particular feed, stuff like that).
It is important to keep in mind it is not a right or wrong thing, it is a why thing. The right and wrongs, like many things, will come out at the end of the process.
In a TAPROOT investigation, we basically keep asking why. Ask the first question, why is only one comb freezing. Every time you identify a possible problem, ask why. Best to do it on a white board and make a flow chart, so you don't loose your mind. Generally speaking, it takes about 5 levels to get at the real problem. Good part is, down that deep into the original situation, you will find that many other issues will be solved as well.
With that said, you may find that you just happen to have a bird that is susceptible to frostbite, but you will have gained a great deal of knowledge in the process.
Did that even help???