たべかす

たべかす【食べ滓】

〔口中の〕 a food particle 《caught between the teeth》; 〔残り物〕 food left untouched; food left over (after a meal); leftovers.

●歯についている食べかす a food particle sticking to a tooth; (bits of) food between [sticking to, stuck to] one's teeth.