Old sesame and rotten millet, an idiom in China, is pronounced as chén chén zhéma làngǔ ng, which is interpreted as outdated or irrelevant things or words.

Source:

I need an old friend to have a place to play with his old millet and rotten sesame seeds (Lao She's Four Generations under One Family II).

Synonym: nonsense:

Nonsense, Chinese vocabulary, pronounced fèi huà, means meaningless words.

Source:

Lu Xun wrote an addendum to the reader: "After copying the collation form, I feel dizzy and don't want to write any more nonsense."