1 & 2: You can find these two gas cans in the park with the cannons in it. One will be against the wall to the left of the centre cannon and one will be in the back right corner behind the cannon.
3: Across the street from the cannon park will be this gas can, next to the blue building.
4: For this can, go to the beach, but before hitting the sand, go down to the right along the boardwalk and reveal a ramp at the end. Walk up and the can will be in a small room there.
5: Immediately next to the ramp you just revealed, there will be a wall you can remove. Do so and another can will be inside.
6 & 7: Go to the burning building and make your way to the rear of it. There you will find a staircase that you can reveal. Head up the new stairs and the can will be there. From the first can, you will be able to see another on the adjacent rooftop. Teleport over to grab it as well.
8: At the cemetery entrance, look for this ghost leaning against the wall and then teleport through the opening in it. On the other side will be the gas can.
9: From the previous can, follow the cemetery wall around to the right and it will lead you to this next can.
10 & 11: Enter the construction area directly across from the cemetery entrance and possess the cat. Once you do, you will need to climb up the scaffolding on both sides to reach these two gas cans up above.
12: To the right of the gas station a little ways, there is a picnic table and a burning building. Look in the right corner to see this can there.
13: In the park with the cannon across from the gas station, you will find this can near a removable wall.
14: From the location of can #3, make a left and then a right to come to a wooden fence. Go through it and you will come to an alley on the right. In that alley you will find this can.
15: When you grabbed the previous can, you’ll notice a cat there. Possess it and then take it to the end of the alley where it will hop up on some dumpsters, climb a lattice and eventually come to the can on the upper balcony.
16: For this final can, go to the entrance of the mental hospital and head through the bushes on the right to the far back.