I was shopping for home stuff in the paint department at Home Depot
today when I saw a small funnel, about the size of a small drinking
glass. It is made to snap onto the neck of either a 1 quart or one
gallon container screw-cap neck--or presumably larger, though I've
actually tried it with both of these sizes.

It makes it possible to pour oil into the vanagon easily, because it
attached at 90 degrees to the can, sticking out the side at whatever
angle you want, parallel with the top of the can.

Very slick, $1.70. Made for Vanagons, though I'm sure the
manufacturer doesn't know that. I replaced my big long funnel with
this one, which will fit in a lunch-sized plastic bag for cleanliness.

It's called a Snap & Pour Spout, marketed by Klean Strip.

Jim