Saturn daan is given on Saturday: black sesame seeds, mustard oil, black cloth, iron. Charity addresses a graha without amplifying it, which is why it is prescribed where a gemstone is withheld.
Daan is charity aimed at a specific graha, given on its day and matched to its significations. Classically it is the remedy that works when a gemstone would be dangerous — it addresses the planet without amplifying it, which is why it is prescribed for Rahu and Saturn where stones are withheld.
Saturn charity is black sesame, mustard oil, iron and blankets, given on Saturday to labourers, the disabled and the elderly.
A difficult Saturn reads as delay, isolation, chronic strain and a sense that effort does not convert. Saturday service to elders and labourers, and Hanuman worship, are the classical response.
Saturday. Fasting, charity and mantra japa for Saturn all belong to that day.
The mantra, the weekday fast and the charity are safe for anyone — they address Saturn without amplifying it. Blue Sapphire is not: a planetary gem strengthens whatever the graha is already doing, so it needs a chart reading first.