Nubayshah (radiyallahu’anhu) reported that Rasulullah (sallallahu’alayhi wasallam) said:‘Whoever eats from a plate and licks it (after meals, using his fingers), the plate seeks forgiveness on his behalf.’(Sunan Tirmidhi, Hadith: 1804)
This Hadith is suitable for practice. In a Hadith of Sahih Muslim, Rasulullah (sallallahu’alayhi wasallam) encouraged the above, and said: ‘…for you do not know in which part of the food lies the blessing (barakah).’
And Allah Ta’ala Knows best,
https://hadithanswers.com/benefit-of-cleaning-the-plate-after-meals/