I think any kind of salt is okay (but it seems a waste to use regular/fine salt or iodized salt because it's been processed more). Sugar should work as well, I think? The key is to lower the freezing point of water so that the ice will melt more quickly. Without the salt, the ice cream making process probably would not work.

I did try it earlier! It seemed to work okay but I guess I didn't shake it hard/long enough because there were lumps, but it was still mostly liquid by the time I got bored and decided to eat it *g*