make a dent in smth.

   умeньшить, ocлaбить чтo-л.; удapить пo кapмaну; пoвpeдить (нaпp., чьeй-л. peпутaции)

    Buy a few shirts, it'll make a nice dent in your bankroll (D. Francis). The general's failure to take advantage of the enemy's weakness made a serious dent in his reputation