We are purchasing a house that needs some TLC. One of which are the gigantically long (90ft?) property line walls that are looking pretty sad. Any ideas on how to spruce them up? They look like over time dirt or minerals have wept down into stains. Our budget isn't big for this project, so any ideas on how to clean them up? Either washing or "bleaching", etc? We looked into an acrylic stain, but it's too big of a project I think and $$.

Thanks in advance for your ideas. :)

p.s. It's the wall in the background (not the near white one)