is the sun (our sun in the solar system) dirty? can it get dirty?

luckily, in a few weeks, idiotic trolls like this one will be gone.

Like no, Skippy.

Well... sorta. 

There's no doubt that comets & asteroids pummel the sun every so often... the material in those objects can be described as 'dirt' - metals, silicates, etc.   Those fall into the Sun, and become part of it. 

That being said, the atoms are then ionized - stripped of their electrons; compounds break apart, as atoms can no longer be bound to other atoms, so... you essentially have the basic elements that went into the chemical makeup of those objects on/in the Sun (and, a good portion is likely blasted into space as well...) So - the chemical elements that used to make up 'dirt' may exist there, but becoming part of the Sun means they're no longer bound to other atoms that *make* "dirt"...  

No, the sun is not dirty, it can't get dirty, it doesn't have dirt on it.

Dirt - no.  Of course when you realize that it is a continuous nuclear furnace and at some point in it's cycle it will make (and then fuse) carbon, you could argue that it is. Still, in the sense you appear to mean this, "no".