You can also find transmission / pressure oil (hydraulic) - think Parker filters - they sell screw on holders.
I bought a set from MSC to filter out the cutting oil on my large Horizontal saw. I pumped the oil through it out to the metal saw blade.
It would be a gravity flow down through it - but the filter works.
My filter lasted for 7 years - filter was still working - but getting heavy - I sprung a leak and the old filter can was dumped. Screwed in my replacement (bought two at the time) and it is running. Bought two replacements next time I went to MSC.
Mart> Mother Earth News had an article on making your own oil filtering device