Well, I did get some filter oil.... It's really weird stuff. It's a really thin oil, but once it dries it get tacky and makes webs when you touch it and pull your finger away. I can see the advantage of using it. It was $6 for a can.
I only used a little, and wrapped the filter in a paper towel to squeeze excess off. I hope ther isn't too much oil in it. I'd have to clean it all out and make sure it's totally dry , and re- apply it.
Another plus- it's water repellent.