Mentioned that German test from YT in thread on "bleaching darks".
No subtitles in English for our end, but did put up a translation of a sort.
https://www.automaticwasher.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?94241_19
One of the "tips" is old method of mixing a bit of powdered detergent with water to make a paste, apply to stain with a small brush or something, rub in, wait a bit then wash as normal. Packets of American laundry detergents offered that advice going back at least to 1970's. It was also in all sorts of consumer/housekeeping advice or manuals.
No subtitles in English for our end, but did put up a translation of a sort.
https://www.automaticwasher.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?94241_19
One of the "tips" is old method of mixing a bit of powdered detergent with water to make a paste, apply to stain with a small brush or something, rub in, wait a bit then wash as normal. Packets of American laundry detergents offered that advice going back at least to 1970's. It was also in all sorts of consumer/housekeeping advice or manuals.