gather dust

Verb

gather dust (third-person singular simple present gathers dust, present participle gathering dust, simple past and past participle gathered dust)

1. (idiomatic) To remain unused for a long period of time.
   • Since he bought the book, it's just been sitting on the bookshelf and gathering dust.
   • As we contemplate the half-finished arterial roads and electrification plans of our own age, and the town-planning schemes that gather dust in the public libraries, we can admire the drive and action of the railway pioneers.1951 December, Michael Robbins, “John Francis's "History of the English Railway"”, in Railway Magazine, page 800