We had a grease can under the sink when I wasgrowing up. My fiancee and I use an old jar. I can't believe people didn't know better. They probably think it's fine to dump car fluids in the storm drain too. Idiots.
The shop I worked in, and I assume most other shops in a cold climate, had a waste oil furnace. We'd save oil all summer, and it would keep the shop warm all winter.