I realize this sounds a little on the unusual side of things; however, last night I was applying some wax toilet ring seal to the tenons (thread wrapped tenons) and was in a hurry to play. After applying the wax to the tenons, I put together my flute and neglected to wipe the wax off of my finger tips and the pads of my fingers and found that as I played, it seemed as though my fingers were making a better seal on the various tone holes. In my opinion, the notes were more crisp/clear and the sound was improved. It may have been a combination of sealing up any air leaks around the tenons and producing a better seal around the holes, I don’t know; however, it did make an improvement in the sound and was easier to play. I might make mention that the amount of wax on my finger pads was very small, yet I could feel that it was there. 
oh my
Initially I thought that psychodonald’s observation sounded a little wacky, and maybe others may have mused something similar.
( no offence intended ) Then I took the trouble to consider the observation, and after all “an observation” it is, and two questions immediately came to mind.
The first was the diameter of the tone holes on said flute. Also that coupled with and in relation to the size of your fingertips ( I’m assuming from what you say that your not using a pipers grip ). The reason I mention this is that, from my own observations, if I’m playing a large tone holed flute, especially if I’ve been playing small-medium holed ones, and I then swap for one with large tone holes, it takes a little while for me to adjust to covering the holes cleanly and effectively. When you think about it, there is less overlapping flesh available to seal the larger tone holes. If your digits are anything like mine ( average ) this is more critical when playing, for example a Boosey & Hawkes Pratten. ( less room for inaccuracy ) Some fingertips countersink some way before the seal is made . In this situation I would imagine that any wax or grease on the fingertips could only assist in stopping the air flow more effectively, where less tissue is coming into contact with the outer surface of the flute. It may only be marginal, but as most of you will know, it takes very little air loss to make a huge detrimental effect on tone and volume. Looked at under a microscope, or even a decent magnifying glass, will reveal just how ridged and uneven fingertips actually are ( helped to stop us falling out of trees at some point in our evolution no doubt 
) I suppose it could also be stated that the wax would have a greater ( if less noticeable ) effect on a small holed flute.
The second, and more obvious detail would be, now that you have all your threaded joints nicely sound and airtight, to wash your hands thoroughly and repeat the exercise playing the same tunes, and see if there is any noticeable difference.
At first I was mildly amused, and now you’ve got me curious. Can’t wait for the next episode 
I occasionally have difficulties covering the left hand holes if I have been playing guitar a lot and have built up calluses. Its not so much hole size as hole stretch - so I notice it most when I am tuning and testing my low flutes, where any leaks dramatically affect the tone. Occasionally I have had to tape up the holes on the left as I am tuning the ones on the right. But I have also been teaching myself the piper’s grip for the left hand which helps.
Casey
I think any sort of grease: Eucerin, almond oil, Vaseline, or toilet seal wax is going to improve the seal. The downside is its a little sticky, so might slow your fingers more or less depending on the substance. I have a friend who swears by rubbing his hands with Eucerin before playing. What is the affect on wood? And what’s in that toilet seal wax?
Don’t ask…
Well, I’m glad you asked!!! It’s “100% petroleum wax,” whatever that may mean. I keep the product in a brown paper sack so as not to alarm family members. 
And no, I’m not going to use any on my lips. And Two Toots, it is exactly as you suggested. I have been playing a small holed R&R type and have been working on a Pratten style, to be more specific a Somers Pratten type flute. Top hand (left) I use my finger tips, bottom hand (right) I use a pipers grip. I will give it the acid test tomorrow night and do a proper “test, re-test format.”
Good point with the Calluses on fingertips from guitar playing Casey ( especially steel strung acoustic ). When I first began flute playing on a keyless, I employed piper’s grip for this very reason, but later dropped the style when I assumed it would be a hindrance when playing the keyed variety. Anyone playing fingertip style flute with soft pliable flesh in these parts of the anatomy has a distinct advantage over those of us with more workmanlike hands. Come to think of it, I’ve two fingertips on the left hand that are badly scarred after being crushed in a childhood accident that have not knit back evenly.
I always knew deep down ( or should that be superficially ) there would be a perfectly logical reason for my often abysmal playing
I keep a tin of “gardener’s balm” in my pipe case (it is basically beeswax and olive oil) and apply the scantest film to the skin where it contacts holes on the days when I am getting leaks, or when I am performing and nervous. I find this makes a big difference.
As an aside, I worked a lot when I was young and foolish with a chemical that causes nerve damage, so I am losing feeling in my fingers, so in general I have problems feeling and thus finding small holes-big holes give me more tactile cues. I notice leaks when I am changing chanters in different keys, or between chanters in the same key with different hole size and spacing.
Hugh
Some of the pipers I know swear by Bag Balm.
Seamus Tansey licks his finger tips:
https://www.youtube.com/watch?v=m1m1KMtIjWA
at 1:32 in the video.
That’s because he likes the taste of Wax Toilet Seal. Great video, really interesting. Thanks.
If the taste of toilet wax could make me play like that I would eat the whole ring.
pshycodonald wrote - " I will give it the acid test tomorrow night and do a proper “test, re-test format.”
Any interesting revelations for us, or did someone hide the soap?
Sorry folks, I haven’t been able to perform the acid test as proposed. I accidentally got some toilet wax seal on my lips and they have been stuck together for past day and a half. 
Just kidding!! Truth is that I just haven’t been able to practice as my job has kept me extremely busy; however, I promise, without fail, to give it a proper go this coming Saturday, 3/5/16 and report back. I’ll give it my best effort to be objective and unbiased, as much as is possible, with such a sticky subject. I know that Jim can hardly wait.
Well, the results are in, finally. As subjective as all of my efforts have been, I’ve come to the conclusion that the wax does assist with a better seal on the large tone hole flute. I took Two Toots suggestion and replicated the same tunes, with cleaning of the hands in between and then tried the same exercise on the flute, sans wax, several times with small breaks in between.
Much as hpinson and others have suggested, I found that the toilet wax made the flesh on both hands more supple and evened out little irregularities (Two Toots), thus, in my opinion allowing for a better seal on the large tone holes. I suspect that it most likely makes little difference what product is utilized, only that the addition of some type of skin hydration seemed to assist me in the production of a better sound. I plan, over time to try some of the products mentioned in the various threads as I can use all the help I can get. I share the concerns that adding various oils to ones hands, prior to playing, might have a deleterious impact upon a wood flute, a chance that I’m not willing to take at this point in time. Casey, in his care and instructions sheet that accompanied my boxwood flute, encouraged the washing of ones hands before play, a practice that I have followed. His point, if I understood correctly, was to, in part, reduce the amount of dirt that can be transferred to the boxwood, making the flute appear unsightly and difficult to keep clean–a point well taken. Two additional points before I close, the flutes I used were made of Delrin and Ebonite, two products that I felt were less likely to be damaged by the addition of a petroleum based mixture. The second point is that I tried the same process on a smaller holed flute (R&R model Ebonite flute 8 keyed) and frankly didn’t notice much difference overall, until I tried playing the low C and C# keys. Much to my surprise and pleasure, I was able to hit those two notes with relative ease and to sustain the notes; perhaps it was practice effect or may be the addition of the wax, I’m not certain at this point.
Well, there it is, with all of my subjective, anecdotal observations, perhaps best left in the area of further interest and inquiry. If nothing else, it was fun and I appreciated the comments–all of them.
Here’s A Suggestion - Sweet Almond Oil may be a safe alternative, as it is used in many health products, being beneficial for; heart, skin and hair. It also has culinary uses. It is rich in vitamin E, proteins, Potassium and Zinc. BITTER ALMOND OIL SHOULD BE AVOIDED - as it contains a toxic acid ( hydrocyanic ) and can be FATAL if ingested. Sweet Almond oil is made exclusively from edible Almonds, so assuming you do not have a nut allergy, it should be safe to apply a tiny amount on your fingertips before playing the “Large Holed Beasties.” As many players already use Sweet Almond Oil to treat their flute’s bore, I can’t see it being detrimental to the woods’ outer surface.