The walls have a sprayed on sand-like texture that is very, very rough. If you brush up against the wall, it can take your skin off! The current paint is a latex semi-gloss (don't remember the brand, but it was probably pretty cheap because we were painting the whole house at the time and didn't have much money or know anything about paint).

I'm planning on painting with Muralo Ultra eggshell in a light green color (current color is white). Here are my questions:
1) What should I clean the walls with? I was going to use Dirtex (I wouldn't have to rinse, right?), but the guy at the paint store said I should use TSP because it will etch the semi-gloss better.
2) Should I sand? Sanding would probably just knock off some of the texture, I was thinking.
3) Do I need to prime? If so what product should I use?

Thanks!
Liz

In THIS case (which you described very well!), I WOULD sand the walls with a pole-sander and 100-grit drywall screen.

YES...You'll have a sandy mess!
The end result?
* A much smoother wall for your skin...AND resale!
* If you have a palm-sander of some type, it would make the sanding a little more palatable.
* Higher areas would necessitate the pole-sander approach.
* Wipe down walls thoroughly to eliminate dust, let dry, and prime. You could use a weak solution of Dirtex for this.

YES..this IS a pain, but when you're done smoothing things, you'll be glad you did!

Primer?:
Any decent primer like Zinssers'123, ACE's Stain-Halt, or C2-One.
Don't use a weak "Drywall/PVA"-class primer for this project. There's much better choices!

Faron