Stale Cookie by Sergio Martínez Cid

Stale Cookie deletes stale browsing data — data belonging to sites you haven't visited in a long time — while preserving everything from the sites you actually use.

What it does

• Scan with preview. Finds cookies, browsing history and (optionally) download history from sites you haven't visited in a configurable number of days (90 days for cookies and downloads, 180 for history by default), grouped one row per site. Nothing is deleted without you seeing the list first.
• Protected sites. An explicit list that no scan or clean ever touches.
• Undo. Deleted cookies can be restored for 24 hours while the browser stays open. (History and downloads are unrecoverable by nature — the confirmation says so before you delete.)
• Automatic cleaning (opt-in). A scheduled clean of exactly what a manual preview would pre-select, recorded in the action log.
• Reminders. A toolbar badge — and, optionally, a system notification — when it's time to clean.
• Action log. A local record of what was deleted, kept for 30 days, exportable with an anonymize option for bug reports.
• Firefox extras. Container cookies and partitioned (CHIPS) cookies are handled and labeled in the preview.
• Dark and light themes. English and Spanish.

Privacy

No network requests, ever. No telemetry, no analytics. Everything the extension needs is stored locally in your browser and never leaves it. The extension runs no content scripts — it never reads or touches web pages. Full policy: PRIVACY.md

Known limitations

• Firefox only exposes the current session's downloads to extensions, so older download entries can't be listed or deleted per site.
• Cache and saved form data can only be cleared globally (the browser offers no per-site API) — that lives in a separate action with its own explicit confirmation.
• Desktop only; sites are matched by registrable domain (visiting mail.google.com keeps google.com data fresh).

Open source (MIT): github.com/SergioMartinezCid/stale-cookie