What is the ruling on sitting on very small food remnants, and on spitting out food remnants from the mouth?

Sitting on leftover food is disliked due to its degradation. Discarding food remnants from the mouth and what is stuck between the teeth is preferable, as cleaning the teeth is more complete, purer, and further from dental disease. A person should floss their teeth after eating to remove whatever is stuck, and use a miswak to purify the mouth.