In Deja Vu, you play an amnesiac detective who's been framed for murder. You have to clear your name and implicate the bad guys. You do this by going around the city and searching for clues, both real and planted.

Eventually, you have to go to the police with what you find to clear your name. But if you have any incriminating evidence against you, you go to jail.

So, you have to get rid of the incriminating evidence. You do this by going down to the sewer.

You can throw anything you want into the waters down here and it'll disappear forever. So all you have to do is throw away the stuff that incriminates you and you're home-free.

How do you know what you should throw in?

Easy, just throw everything you have in. Your character is a good enough detective that he won't let you toss anything that you'll need to clear up the mess. So just throw in everything you can, walk to the police station, and win the game.

You'll probably want to wait until you've gathered all the evidence first, though. Otherwise you might get stuck.