How do you use shaders in toribash version 3.41?

Open toribash ( of course, :P)
Go to the menu by pressing esc if your in-game, if you have it started just read below..
then go to options then settings then find shaders and erase the "0" and type "1" if the game crashes that means your computer can't run shaders.

Hope that helped.

It didn't work, and it didn't crash. I changed it to "1", pressed enter, and then nothing happened.

Either your graphics cards isn't up to the job or you need a driver update.