" After washing the vehicle, always:
Remove the left fairing
Remove the cap
Empty its content into a container and deliver it to a salvage centre"
As I've recently done my first washing

I don't think that i had to do that in any other bike!
Is it necessary?
What is this cap?
What's the problem if i don't do that?
P.S. You may have already discussed that in one of the other Italian forums, but my Italian are not that good yet!! Hopefully in a few months (years?)