From Sahih Bukhari (Hadith 3072):
Narrated Abu Huraira:Al-Hasan bin 'Ali took a date from the dates of the Sadaqa and put it in his mouth. The Prophet (ﷺ) said (to him) in Persian, "Kakh, kakh! (i.e. Don't you know that we do not eat the Sadaqa (i.e. what is given in charity) (charity is the dirt of the people)
Reference: Bukhari 3072