For camping in the Boundary Waters Canoe Area in northern Minnesota where cans and glass bottles for food are illegal, I use these for cooking oil and squeeze margerine:
http://www.rei.com/product/605499
For tobasco sauce I don't need 4 oz, instead I use this:
http://www.rei.com/product/605500
The lids have to be threaded onto the bottles very tight, otherwise they leak.
I carry these bottles inside a plastic bag that is inside of another plastic bag because when you open and close the spigot a couple times a day, a bit of the cooking oil starts to coat the bottles. I suspect you would want to carry the bottle in plastic for the same reason but at least 99.99 percent of the proofhide would stay in the bottle.
They also make a 3 oz size in event you get on any airplanes and have your liquids in your carryon. I was in the local REI store last week looking to buy another, they were out of stock on the 4 oz size so I looked at a 3 oz size for olive oil, I noticed that the 3 oz is much stiffer plastic than the 4 oz.
http://www.rei.com/product/753331