The best open source alternative to BleachBit is Pearcleaner. If that doesn't suit you, we've compiled a ranked list of other open source BleachBit alternatives to help you find a suitable replacement.
BleachBit alternatives are mainly System Cleanup & Optimization. Browse these if you want a narrower list of alternatives or looking for a specific functionality of BleachBit.
Mac app uninstaller that finds and removes associated files, orphaned leftovers, and development artifacts across macOS 13 and later.

Pearcleaner is a Mac desktop app that handles what the default drag-to-Trash uninstall misses. When you delete an app on macOS, support files, caches, preferences, and other associated data often stay behind scattered across your system. Pearcleaner finds and removes all of it.
It supports drag-and-drop uninstalling, a Finder extension for right-click removal, CLI support, and deep link automation. You can view installed apps in list or grid mode, with badges identifying web and iOS apps.
Key capabilities:
Customization covers theme colors, adjustable search sensitivity, and include/exclude rules for which directories get scanned. Full Disk Access permission is required to search system locations, and a privileged helper handles actions on protected folders.
Pearcleaner runs on macOS Ventura (13.x) through Sequoia (15.x) and is licensed under Apache 2.0 with a fair-code restriction that prohibits monetization of the app or any modified version.