Morocco "Walking around" money

Hi -

I'm going on a cruise(SPV Royal Clipper) in November that will be calling on Casablanca and Safi Morocco.

I'll be taking tour of the city in Casablanca, and just walking around Safi. Will I be able to use US$ or Euros for small purchases like a soda, or small souvenir items?

On a related note, is it customary to tip your guide/driver after a tour? What's the nominal amount?

Aloha,

John

I'm adding a 2nd question about Morocco in hopes that some one will answer either my 1st or this question.

Has any one stopped in Safi? Is it a walkable distance from the cruise port to the Pottery quarter?

Thanks in advance!

Aloha,

John