কেতু daan is given on মংগলবার: রংগ-বিরংগা বস্ত্র, কালে তিল, সরসোং কা তেল, কুত্তোং কো ভোজন. 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.
Ketu charity is multi-coloured cloth, sesame and blankets given to ascetics, and food for dogs — the animal traditionally sacred to Bhairava.
An afflicted Ketu reads as sudden loss of interest, confusion about direction, and withdrawal from what one had built. Ganesha and Bhairava worship, feeding dogs, and steady practice are the classical response.
মংগলবার. Fasting, charity and mantra japa for কেতু all belong to that day.
The mantra, the weekday fast and the charity are safe for anyone — they address কেতু without amplifying it. লহসুনিযা is not: a planetary gem strengthens whatever the graha is already doing, so it needs a chart reading first.