MK3? Sounds like your charcoal canister. I can't remember off the top of my head how it comes out, but I don't remember it being too bad.
I'm replacing my passenger fender and I find weird box above the inner fender and tuck into the ext. fender. 1. What does this box do? 2. How do I remove it so I can get to that last bolt? Any suggestions appreciated, especially if you make me laugh.
If its an MK3... its probably the vacuum expansion tank you're looking at. White box that's empty and has a white hose coming out of it? You don't want to remove that hose. It will mess up the vacuum suction and your door locks won't work. Actually I don't know if that's true, that's just my assumption, but I do know its the vacuum tank. I've yanked the white tube out white pulling a fender liner from a junkyard and it made a loud hiss when the air rushed into it.
Best thing I heard to do with it was to reroute it and secure it under the windshield rain gutters. Its a PITA getting it unscrewed from the fender liner though.