The "Yellow Cans"

The Yellow cans is very easy to see in the environment because of the color.
Although I don't like them, because it reminds me of this oil cans that has been contaminated lakes and stuff. What do you guys thing?? Am I just being a "drama queen"hehe?
We talked about having for example signs made of wood paper because of this organic feeling a zoo should have, and thats why I don't see were this metal ting fits in!
But a bright color (if not yellow) would maybe be a good thing to use to make people see it, in for example the "green line".