Did you really use sand to clean clock parts? Sand?? Please never do that again. That balance wheel swings unevenly and has no power to it. Please clean the pivot holes and springs properly next time or it will not last. You can clean out the pivots with a toothpick and the pivots with polishing compound.
Do both keys wind? If so, there's dirt in the gears or the balance wheel isn't moving for some reason. If not, then one of the winding springs is broken and you'll need a new one. You can buy them if you measure thickness, width and length and source one from a clockmaker supplier.
Take it apart, clean it, put it back together then oil with sewing machine oil. You will only need a tiny bit on the axles that meet up to the plates. Just make sure you pay attention to what you are doing and really look at it before you start, though.
