Scrape the Bottle of the Barrel

Etymology:

• Barrels are used to store many things and when most of the items or things it contains have been used it is left with silts and dregs. Often the residue sets at the bottom of it making it hard to extract it in the urgent time of need. Thus the idiom refers to use worse of something when most of its good part has already been consumed. It also means to resort to last left option when you do not have plenty of options.