When child processes in Node.js don’t exit cleanly, it’s often because they still have open I/O streams (stdin, stdout, stderr) or unresolved tasks. This prevents the process from terminating. To handle this, make sure to close all streams and handle any pending I/O operations properly by listening for the `close` event. If the child process is still hanging, you can explicitly call `process.exit()` with the appropriate exit code, but this should be a last resort, as it can abruptly terminate ongoing tasks. Properly handling the lifecycle of child processes ensures they exit cleanly once their work is done, freeing up resources and preventing leaks.