To create a mild soap solution for cleaning your living room walls before painting, you can use a mixture of warm water and a gentle liquid dish soap such as Dawn or Ivory. Mix about a teaspoon of the dish soap into a gallon of warm water to create the solution. This will effectively remove dirt, dust, and grime from the walls without leaving behind any residue that could affect the paint adhesion. Remember to test the solution on a small, inconspicuous area of the wall first to ensure it does not cause any damage or discoloration. Always rinse the walls with clean water after cleaning to remove any soap residue before proceeding with painting. This method is a safe and cost-effective way to prepare your walls for a fresh coat of paint.