Art Room Cleanliness

Today my first class, a 6th Grade class, used charcoal. Near the end of class during clean up a piece fell on the floor, and got stepped on. So, I have three other classes after this first class. I don't have time to clean up the charcoal. I have other things I need to do in my 5 min break between classes (If I even get the full 5 mins). The charcoal got tracked around the room a bit. I later saw one of the custodians, and asked for a mop so I could clean up the charcoal. He didn't have one to lend me at the time, so I asked him to bring one down later when he got a chance. I didn't ask him to clean anything himself, I just asked him to leave me a mop. I have cleaner that works fine with the charcoal, I just can't wipe it up with a sponge.

So, the custodian comes down during my second to last class of the day, and begins mopping some of the first room, which is barely dirty. Then he comes into my class, though I have a class at the moment, and tries to mop a bit up. Now I know that this isn't very logical, because it's right near some of the tables where my students are sitting, but he does this before I have a chance to tell him not to. Then I proceeded to get into a discussion with him about what it is (we've had this discussion previously when some charcoal spilled already) He believes that it is 'oil' based, which I am not sure of. So while I have a class working, he questioning why it's messy, (um, it's art class) where this charcoal came from, and then if the cleaning solution I had was safe for the floors.
I began to clean up some of the floor today before I left because I felt that I couldn't leave it dirty. I unfortunately didn't get to clean up all of it because it just takes too long without a mop. So, I'm going to bring a mop in so I can get everything taken care of.

I just wish I didn't feel guilty about the room being dirty every time there were just a few more scraps of paper on the floor then usual, never mind paint or charcoal on the floor.