Break Down Walls

[101Titan101]

How do I chip down a wall?

Specifically in Rattlesnakes I've pressed everything using a fork, file and screwdriver but can't break it down.

[Rookie]

If you're trying to chip the double layer wall on the left of the cells it's futile, it doesn't work.
You can chip any wall as long as it's one layer, there's nothing on the other side of what you're chipping and there's only walls near the wall you're chipping (so if you're chipping a horizontal wall there musn't be a door or cell bars on left or right of the wall you're chipping).