Abstract As reservoirs deplete and water production increases, fines production often ensues. The produced fines then cause various forms of damage including screen plugging. To alleviate the plugging, acid washes are pumped onto the screens and then brought back to surface. Often this treatment is only a temporary solution and re-treatment is required. This paper demonstrates a more permanent solution to fines plugging through acidization of the surrounding formation and removal of the source of the fines. In high temperature wells the choice of acid must be done so that the formation is not damaged but the fines are removed. A series of tests done on clay-rich cores shows that a new organic acid in conjunction with hydrofluoric acid can successfully remove fines and stimulate production. Conventional organic acids will damage the screens at high temperatures through corrosion. This new acid has very low corrosion at high temperatures. Corrosion tests show that at 350 °F the corrosion rate caused by this organic acid is 0.001 lbs/ft2 on 22Cr for 16 hours. Core flood testing demonstrates that these organic acid:HF mixtures can effectively remove fines at temperatures up to 400 °F.