Thanks! ***EDIT*** Found out what worked well. Soaked it with Greased Lightning (GL) spray cleaner, let it soak for several minutes, sprayed it/rinsed it the with hottest water I could, then reapplied GL, lightly scrubbed with a small scrub brush to clean out the pleats, reapplied GL, etc. Going through that process about 3 times and letting the filter dry overnight resulted in a nice white filter. Re-oiled and am letting it dry all day prior to reinstall. I wouldn't recommend using any sort of petroleum product (varasol, carb cleaner, etc.) due to the cotton makeup of the filter. Water-based cleaners are the safest and plenty effective.