It's a good cleaner but very drying - hard on the hands.

Here is a link that might be useful: TSP

How high are your ceilings? Could you reach them with a sponge mop, if you stand on the floor? That would be my first idea, but if you have very high ceilings the mop would be unwieldy.

My experience with hairline cracks is that effort of sanding the wall smooth after skimming it with joint compound isn't worth it. However, you might want to try one, see how it goes. I just had my much of the interior of my house painted and the painters skimmed and sanded all the little cracks and the walls look great.

That's another alternative, of course. Pay someone else to do the hard stuff! ;-D

tsp sounds darn useful. hard on hands? little late for that. the wallpaper project has taken years from my life and put them right onto my hands anyway.

the room is on the second floor so the ceiling is not too high. sponge mop might work. w/ a hooded parka.

Tri Sodium Phosphate. A non-sudsing potent detergent.
Wear gloves with TSP. It is best used with the hottest water you can stand through the gloves and it will produce chemical burns on skin.
The 'TSP substitutes' are mostly metasilicate and do not work nearly as well.
Real TSP is not allowed in some areas due to the high phosphorous content.
Drive further unti lyou find it. It is the best cleaner for plaster walls.

You will need to rinse the wall with clean water after it dries from using the TSP.
DO not allow TSP to get on hardwood floors. It will produce permanent stains in most woods.

I have removed wallpaper and repainted in a number of rooms with plaster walls and have not used TSP (nor have I heard of it actually)
I use either vinegar and hot water or DIF wallpaper remover and hot water to rinse off the old glue and then I repair the wall as needed, sand, and then rinse with water. Then I paint. If I wallpaper again I prime with a wallpaper primer first.
If you have stains on the wall you can prime with Kiltz primer or something similar.
Personally if something can cause a chemical burn on your skin than I would not suggest using it, especially overhead!

I used plain hot water and lots of paper towels and a sponge to get the glue off. I've heard the TSP thing too, but it is not good for any sort of textured plaster.

Put some electric tape over the outlets and don't remove until the area is completely dry.

For cracks, I recommend using a powder form of EZ Sand, or other joint compound. You can buy it at Lowes or Home Depot. The premix stuff shrinks up when it dries, this doesn't. Apply with a putty knife, let dry and sand. Use a good primer and then paint. I suggest a flat finish for best results.

morgan88: If the plaster is old and hard and was never painted, you don't have to prime. Our walls have held wallpaper for 150 years and have never been painted or primed.