In some other communities this topic is a much more polarized discussion.
Personally, I have used EVO on my pipe wood and stem both and have been happy with the result. I have only used it occasionally on the wood, and often on stems.
Others echo what daveinlax said, that the oil goes rancid so you shouldn't use it.
I have recently switched from olive oil for the stems to a new prototype product that I have been testing, and it is made by one of the members that posted in this thread.
So far, only test samples have been made, and inventory is not yet available.
When it becomes available, I think it is going to be a huge hit.
I have been using it every day for 3-months and I think it is an excellent solution for preserving stems and bringing them back to life. I think olive oil works great, but this new stem oil blows it away.
I am doing a little consulting on bringing this to market and my first piece of advice was to produce a huge inventory.
(Sorry if that was a bit of a thread hijack. Hopefully the moderators will cut me a break.)