I have 2, one cut off to fill engine oil, one not cut for transmissions or anything with a full tube. I store them on a screw in the wall (hole in the longer funnel, cut off funnel just goes in the longer one). They drain into a catch can I mounted on the wall too. When I need to use one I clean it with brake clean first since they do attract all the garage dust.
There are nice funnel storage solutions out there. I know the tools trucks sell funnel buddies, lisle or someone more reasonable probably sells them as well. They contain the fluid remnants and also shield the top so your funnels don't collect the garage dirt.