It's way cheaper and easier to clamp a piece of appropriately sized rubber fuel line to the end of the (brake/clutch/throttle) cable, add oil, and either let it drip through or add a little air (regulated) pressure. I've ressurected a couple cables (on a Caterpillar grader, for one) that I thought were goners. I always use this method when installing new cables on anything.
I used to run an old 600 Prentice log loader that had about a dozen of these type of cables on it and they gave me a lot of trouble. Seemed every year I'd have to replace one or two of them. I tried just about every petroleum based lubricant you can get....grease, motor oil, WD-40, whatever. One day I was in the parts store and was asking one of the guys about this problem and he hooked me up with a little bottle of dry graphite lubricant. I just poured it in from both ends and shook it around and ran the cable through a bunch until it was well distributed. I started using that and it sure cut down on my cable problems. I think perhaps that since it's a dry lubricant it doesn't attract so much dirt and grit. Not saying it's the grand champion of all fixes, but it sure worked for me.
One of the funniest tricks i've seen was for freeing up past american style cables. The ones that are flat wire wound around the sliding cable , without any other sheathing or protection. Of course they would freeze up if not lubed. Get a car battery, some jumper cables and attach one jumper to an end of the cable and then the other at the other end, wait a few seconds until it gets red -NOT TOO RED ! While laughing hose down with cold water. Soak it with ATF [or whatever] . Fun
That IS an interesting fix. Wonder how they came up with that idea?
my favorite is cut a chunk of intertube out and hose clamp it around the cable, then add oil of your choice and hang the cable.
getting a cable red hot and soaking it in ATF would be fun too tho!