EASY, CHEAP, CLEAN AIR.
I used an old mini compressor tank - pump died.
Stood the tank on it's end.
Where the big standpipe with gauge,etc was I made an inlet fitting that forced the air to swirl around in the tank in a spiral motion. Just a blocked end on the inside end, with a small saw slit on the side.
The outside has a one way valve so when compressor turned off there is no backflow.
Another fitting nearby, which was the compressor inlet is now the outlet, with a gauge on it and a few fittings and a tap.
I've used it on polished stainless and not an oil or water mark, ever.
Used for 800 hours, running small volume for swarf removal.
Thought I'd better empty it. Waste of time. Do it in another 2 years.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.