My entire sword maintenance routine consisted of cleaning my steel after ever training session with WD40 (or its equivalents), sandpapering off any rust spots as they appeared and leaving it at that. It has done me surprisingly well but my older swords tend to be spotted with rust where I've missed a cleaning session or left the swords for a period. I'm now aware that while WD40 is great for cleaning it does little for long term protection because it evaporates and is hydroscopic, i.e. attracts water. Great quality for cleaning, lousy quality for protecting between uses.
So I've been on the hunt for something good to look after my steel with. In the main the choice seems to be come down to wax or oil, to find out what is good I've bought one of each and what follows are the results of my comparison.
For the oil, I followed a tip off from a friend that bike chain oil was really good for sword care, I got a can of Castrol motorbike chain oil. As my friend put it the theory here is that motorbike chain oil:
1. Will have a higher viscosity being designed to stay on a motorcycle chain with minimal throw off. If it can do that, it can stay on a sword pretty easily
2. Because it's designed for use on a chain it's not designed to be hygroscopic but to repel water
For the wax, I've bought a tin of Renaissance Wax which seems to be the product of choice by most suppliers of sword gear. As a product specifically designed for preserving I was expecting big things.
Pros: super easy application just spray and spread. Easy to ensure the steel is fully covered including all the awkward places around the hit furniture, oil also seems to flow to fill in any gaps that forms due to bumps and scrapes. Finger prints don't seem to get through this and a bit of casual handling doesn't seem to affect it at all. I've used it on my sharps and had a round or two of plastic water bottle bashing with great results with the water beading up and rolling off very easily. Even after wiping down the blades afterward there was a good layer of oil left. Finally, this oil was cheap $7 for a can that'll probably last me forever.
Pros: it's still pretty easy to get this on your blade, not as super easy as oil and it does take more work to get a good covering, however it's not bad. Have to do a bit of work to get it into the awkward places. It definitely attracts less dirt than oil though it does accumulate it over time. It's pretty much bullet proof in terms of protection, 100%. Once it's on, it's on and it doesn't come off meaning the protection is excellent. It's also a plus that this can be applied to preserve the leather on the sword.
Cons: Once it's on, it's on. So I've found that while it takes a while to get dirty it's much harder to get that dirt off. I've found the best thing to do is simply rub the whole thing down with a cloth and apply more wax. It doesn't seem to get as clean and a de-greasing but it's acceptable. Finally, the wax is actually pretty expensive, $25 for 65ml. Will have to see how far this takes me.