How do I clean a dust & grease filled wall?

TSP is what I would use. That stuff will clean anything!

We are here you you, take it one step at a time. Renovating an entire house is a big job, especially if you are doing a lot of the work yourself. Make time to stop and admire your progress too. Take a night off and grill up some dinner and relax here and there.

I use degreaser..... Dollar Tree Awesome Degreaser and 1/2 gallon Awesome Orange. I use a car sponge and little round plastic scrubbies. Mix the Awesome Orange in hot water and use the sponge to wipe down, then for tough areas spray the degreaser on and use the round scrubbie. I wear kitchen rubber gloves as it can be hard on the hands.

What is the wall made of and do you know if any of what is on it is build up from a smoker living there? What you use to clean an exposed brick wall will be different from a painted wall, a wallpapered wall, a paneling wall (which could be wood or pressboard, requiring different cleaning methods).

Whatever the type of wall, I highly recommend vacuuming it first with a brush attachment. You will save yourself a bunch of trips up and down a ladder with a bucket by vacuuming as much dust off first as possible.

Also, protect the floors. Use plastic drop cloths taped to the baseboards so that if you slop water or cleaning products on the floor it doesn't matter so much. Tape them to the baseboards rather than the floor so you contain any puddles rather than having them soak under the baseboards and show molding.

If the wall is highly textured, use a brush to scrub and a rag to dry. If the wall is painted, a gentle scrubbing tool like the plastic scrubby suggested above is a better choice. If the walls are paneling, you need to keep them as dry as possible while also scrubbing well, so use cheap washcloths (like you might find at Big Lots or someplace) because they have good texture without being too rough. If it's wallpapered, strip the paper and start fresh. Real wood paneling you might want to use Murphy's Oil Soap rather than a harsher cleaner. Pressboard paneling you need to take extra care to avoid getting the joints wet (they will absorb water and then start to flake apart).

If a smoker lived there, you are cleaning tar as well as grease. That might require a different kind of cleaner. I have found window cleaner (used straight and then rinsed) to be the most effective at cleaning smoker build up. Make absolutely certain the rinse water is clear before thinking you are done. If you paint over smoker residue, walls will likely seep yellowed droplets of nastiness anytime it's really humid.