I remember those too. I even have a spout in the plastic tub that I store tools that are no good in. I also remember my Grandfather the farmer buying motor oil in 5,20 and 50 gallon drums. You would pump the oil into a glass Mason jar and it had a metal spout that twist on to it. Its been awhile since I've seen any of those in a swap meet. Whats really weird is that even on the new plastic oil cans those older small neck jobs are being phased out and replaced by the large mouth ones. The last time I bought oil only the cheap stuff was in the small necks.
Remember the quick and dirty way to open those old cans? You took a screwdriver and hit the handle with your palm. You also got a little burp and some would squirt out when you went to pop the vent hole 180 degrees around. If you hit hard enough and at the wrong angle the paper cans would collapse making a bigger mess.
Some of you may also remember that anti-freeze also came in 1 gallon square cans. Some of the cheap stuff didn't have a reusable cap to twist back on. Man the Greenies would have had a heyday back than.