I have been doing it “forever”. It is messier than bar oil since it is thinner. But it flows really well. Sometimes I will give the chainsaw a quick rev to throw a line of oil where I want to cut. It acts like a marking pencil.
Whenever I flip the bar and replace the chain, before I start the saw, I dip the front 3–4 inches of the bar into a coffee can of used oil to pre-lube everything. I pull the chain around by hand to make sure everything is coated. Then I start it up.
When I am finished, I slip the bar and chain into a plastic bag so it does not drip all over the place.
I keep the used oil in gallon jugs and give it plenty of time to settle before using it. I never use the sludge at the bottom. That gets recycled eventually or is used for starter in my fire pit. A guy I know keeps magnets in his oil jugs to grab metal particles. I don’t bother.
I figure this method is 100% recycling and much better than sending oil back to the refinery where it will be cleaned, reconstituted, and repackaged and shipped back to the store where I have to go buy it and bring it home.