I found many years ago that oil by the galon like WD-40 is cheaper than small cans of three in one. But, how to get the oil from the galon to the small can?
I took about four inches of surgical tubing, and pressed it onto the end of the squeeze can. Hold the small can with cap up. I took a small pill bottle, and filled it from the big can.
Hold the small can upright, and put the end of the surgical tubing into the small bottle of fluid. As I squeeze the small can, bubbles blew. When I released, fluid came back into the small can.
I'd be squeezing air out, and the fluid stayed in the bottom of the small can. I could refill a small can in a minute or less.