Got any (housekeeping) cleaning tips to share?

The not very well-known cleaning tips I am looking for.
The ones you inherited from grandmother/-father.
The ones you discovered yourself, by serendipity.
Or the ones you found through a Q&A site ;-)

Window cleaning: use water with vinegar, wipe/polish with old newspapers.
Works like a charm!
Edit: And liquid olive soap works great for faucets; they’ll be shiny!