Angry Birds Trilogy

For this achievement, you have to break all golden wrenches in the Bad Piggies episode of Angry Birds Classic. There is a counter if you go into your statistics and scroll down, but it won't tell you which wrenches you're missing. Though once you get one, that wrench will turn brown on any subsequent plays of that level, so it shouldn't be hard to find a lone missing one. Here is my list of all the wrenches, and tips on how to reach them.
There are 20 wrenches in total, but this list is ordered by level numbers, so don't get confused over that.

1:
Left side - Shoot blue bird straight ahead, nothing fancy.
Backside of the right hill - Knock the rock/tnt on the hill down to hit it.

2:
To the right of the left tower - Break the right side of the roof with the white bird and shoot a red bird at a high arc to hit it.

3:
Middle + Right side - Just fire a black bird in there and he'll usually clear both of these.

4:
Bottom middle - Fire the orange bird through the first pig to get this one.

5:
Top of the top ball - Just shoot this one with any bird.
Bottom - Focus on destroying the main building, and precision bomb the wrench with the white bird if needed.

6:
Bottom middle - The easiest way to get this is to shoot the first blue bird into the ice triangles to the right of the second pig, detonating just before impact. This will often cause the entire level to be cleared, including the wrench.

7:
Middle trench, bottom + Right trench, upper "floor" - Same strategy for both of these, just bomb the bottom of their towers to make them fall and break the wrench.

8:
Three wrenches, all in the bottom middle - An easy way to get these is to just launch the white bird through the first helmet pig without activating the bomb, and she should continue and roll into the wrenches.

9:
No wrenches on this level.

10:
Bottom right - Hit the TNT on top of the wrench with any bird to get this one.

11:
Middle - Just shoot the yellow bird into the gravel blocks in front of the wrench to knock them down on top of it.

12:
On top of the third tower - Just shoot it with any bird.

13:
Bottom right - The easiest way to get this one is to fire the birds fairly high and attempt to topple the right structure on top of the wrench.

14:
No wrenches on this level.

15:
Bottom right - Fling the white bird over the big tower and bomb the glass above the wrench. With a little luck, the tower will topple and crush the wrench.
Top right - All you have to do for this is make the right gravel tower shake enough so the big pig rolls off onto the wrench. I prefer to shoot a yellow bird into the top left corner of the tower.