What they are telling you is to use either a liquid filter oil or a spray on filter oil. I myself like the liquid filter oil the best. You can use Repsol, Motul,etc, the one I like the best is the Bel-Ray, never seen a spec of dust get through it. You have to oil both the red and the yellow foams. For this you have to remove the red one from the yellow. What I do is I put the yellow one in a ziploc bag and pour some filter oil on it, close the zipper and just work the oil with my hands until I see that the filter is fully covered (add more oil if needed). I repeat the same thing with the red foam. Lastly I get a few pages of newspaper and I use them to remove the excess oil by squeezing the filter inside the paper and at the end with some bounty. Have used this method for 15 years and never had a single problem. Always clean your airbox before installing the clean and reoiled filter.