What is the best ongoing charity for the deceased, and does it expiate their sins?

The best ongoing charity (Sadaqah Jariyah) for the deceased is providing water for those in need, such as digging a well. Other forms of ongoing charity include various types of endowments (waqf), such as building mosques, Quran memorization centers, schools, and hospitals. All these, and similar deeds, if their reward is dedicated to the deceased, will benefit them, and the reward will reach them, expiating their sins. When a believer commits a sin, its punishment can be averted by ten reasons, among them: their believing brethren supplicate for them and seek forgiveness for them, whether alive or deceased, or they dedicate the reward of their deeds to them, by which Allah benefits them.