Clinker (natural stone) soil clean (from decades old dirt)
Use concentrated, liquid soft soap (99% biodegradable)!
Apply the soft soap thickly and evenly to the clinker floor. Leave the soap to work for up to one hour (depending on how dirty it is). Briefly brush a bristle brush with short bristles (about 2-3 cm) into very hot water and then scrub the floor vigorously. (Yes, unfortunately it does not work without scrubbing anyway, but our floor was entered for 60 years and never cleaned.) The before-and-after effect is really blatant! The effort is worth it!).
Then pick up the viscous foam with a window scraper and repeatedly rinse the floor with plenty of (hot) water and a floor rag until no foam is left.
It is also recommended to do only one piece at a time (40x40cm). Start in a corner of the room and work counterclockwise (right-handed) "spirally" toward the center of the room. After cleaning a floor piece, smear the next piece to the right. After a whole room cleaning session, the same piece will be ready for cleaning.
In the picture the floor is cleaned on the left, on the right with 60 years of dirt.
