Trunkmonkey: Great idea! I wish I would have thought of using air pressure with a can..its a better idea than mine, as it would not waste clean oil.
What I tried to do (to prevent waste of clean oil) is to "recycle" the oil..its not real dirty like dirty oil, but not completely clean, either, as it has been mixed up with old dirty oil. But it works in an oil can, which I use for lubricating hinges, or anything that needs a few drops of oil. Sure, WD40 spray has some advantages to "the old fashioned oil can" you rarely see mechanics use any more, but there are advantages, too, to the old fashioned oil can, we used often on the farm. Heck, nowadays, mechanics often dont even know what a grease gun is. My son bought a new Kabota tractor, however, and it has many grease zerks, which need greased frequently..or else. Its rather unclear to me why a tractor would need grease zerks, while virtually all new cars have no grease zerks. They are all "sealed". So, why would a tractor have grease zerks and a car not? We also dont "pack" wheel bearings anymore..which we always used to do. My father told the story of his 32 Ford. He said he ran it to fast on low oil, and it started knocking. So, he took the oil pan off, and took a file and "filed down" the end caps of the bearings (making it close slightly smaller), put the used oil back in, and drove off...no more knocking.
There is some truth to Henry Fords statement that "the 32 Ford" is perfect, no research is needed, you cant improve it. While it has been massively improved in many ways, I actually tried "filing down the end cap bearings" on my 55 chevy in line 6 cylinder that was knocking after I inserted new bearings. I had taken sandpaper and sanded off the grooves on the crankshaft, somewhat, and put it back together. The engine started and maybe ran a mile before, when it threw a rod, you knew it was done. I knew then the old school "filing the bearing caps" to stop your car from knocking was over.
Mostly, they dont seem to rebuild (remanufacture) most engines anymore. Yea, you can still rebuild an old Chevy 327, or even a six cylinder. But, you probably wont get a good result rebuilding your 4 cylinder 2005 Nissan or Toyota. Modern engines are manufactured by massive machines with very close tolerances that is exceptionally difficult to duplicate in many/most machine shops. Engines have become disposable, sadly, and are not designed to be rebuilt.