1. First remove the food before getting up and leaving. When removing the dastarkhaan, the following duaa should be read:
اَلحَمْدُ لِلَّهِ حَمْدًا كَثِيرًا طَيِّبًا مُبَارَكًا فِيهِ غَيرَ مَكْفِيٍّ وَلَا مُوَدَّعٍ وَلَا مُسْتَغْنًى عَنهُ رَبَّنَا
All praise is due to Allah Ta’ala, such praises that are plentiful, pure and full of blessings. O our Rabb, we do not regard our praises to be sufficient (for the food You have granted us) nor do we regard our praise to be the final praise (for what You have granted us), and nor do we consider ourselves to be independent (of praising You for all that You have granted us).
عن أبي أمامة الباهلي عن النبي صلى الله عليه و سلم أنه كان يقول إذا رفع طعامه أو ما بين يديه قال: الحمد لله حمدا كثيرا طيبا مباركا غير مكفي ولا مودع ولا مستغنى عنه . ربنا. (ابن ماجة رقم 3284)
Hadhrat Abu Umaamah (Radhiallahu Anhu) reports that Rasulullah (Sallallahu Alaihi Wasallam) would recite the following when the food or whatever was before him was being removed:
اَلحَمْدُ لِلَّهِ حَمْدًا كَثِيرًا طَيِّبًا مُبَارَكًا فِيهِ غَيرَ مَكْفِيٍّ وَلَا مُوَدَّعٍ وَلَا مُسْتَغْنًى عَنهُ رَبَّنَا
2. After meals, wash both the hands and gargle the mouth.
عن سلمان رضي الله عنه قال : قرأت في التوراة أن بركة الطعام الوضوء بعده فذكرت ذلك للنبي صلى الله عليه سولم فأخبرته بما قرأت في التوراة فقال رسول الله صلى الله عليه و سلم بركة الطعام الوضوء قبله والوضوء بعده (ترمذي رقم 1846)
Hadhrat Salmaan Farsi (Radhiallahu Anhu) narrates: “I read in the Taurah that the blessings of food lie in washing the hands after meals. I mentioned this to Rasulullah (Sallallahu Alaihi Wasallam). Rasulullah (Sallallahu Alaihi Wasallam) replied: “The blessings of food lies in washing the hands before eating and after eating.