https://www.ebay.com/itm/392196444984?i crabbed and complained about three 5 gallon cans i bought about 6-8 years ago at the local gas station for 13 bucks a pop !
i fixed them by tearing the spouts apart, gutting them, and using a heavy plastic "push on" cap that fit the spout diameter.
for a vent, i drilled a hole in the top of the can just past the handle, that fits a standard short rubber tire valve stem. it took a little finagling to fish the valve stem through the can to grab the end and finally popping it into the drilled hole. i removed the core, then reinstalled the cap.
works like a charm ! just remove the valve stem cap when pouring, and it lets in just enough air to pour a nice, steady flow without the "glug, glug, glug" that can splash all over.
