Once your filter is clean and dry you can then re-oil the filter by spraying or pouring dirt bike filter oil on the outside of the element, use a generous amount and ensure you massage the oil through the filter so it has even coverage over the entire external surface. If it is a twin layer filter make sure you oil both elements as the oil is what dirt and debris sticks to so the clean air can then pass through to your engine. You should also run a thin bead of grease around the surface of the filter which seals to your bike as the added stickiness of the grease will ensure a better seal!