### What needs to get done Currently, the `clean` method on the executor is very long and complex: https://github.com/canonical/craft-parts/blob/70fc3bac64c17457fd90817fde749cfa8057cd78/craft_parts/executor/executor.py#L155 This should be refactored into some number of smaller, focused methods to reduce code complexity. ### Why it needs to get done There are too many locals and branches to make sense of the `clean` method at first glance.