You can find lots of good rules and procedures about the Math Help Room to pass along to your students at
www.math.purdue.edu/academic/courses/helproom/
Below are some more good suggestions from TAs in the Math 205 trenches. (If you have something to add here, just e-mail it to Steve Bell.)
If a student asks about a problem from one of the MA 260s, tell them that Math 205 is not the place for them to receive help, and do not be tempted to be charitable. Send them away and make sure they don't try to ask somebody else in the room. It is important to get the message out that Math 205 is for lower division course help only. Even if the room is almost empty at the moment, these students should not get the idea that they can come to Math 205 for help. The room is stretched beyond reasonable limits during exam times, and so the rule is definitely NO EXTRA BODIES.
There are subtle ways to discourage students from trying to milk TAs for homework solutions. Here is a sample dialogue to give you some ideas.
Student: Can you show me how to do problem 3? TA: Yes, I can help. Let's see how you started the problem. Student: Well, I didn't actually start it yet. I didn't know how to start. TA: Ok, read me the question and let's see what comes to mind first. Student: (reads problem). I have no idea how to start. TA: Ok, do you have your notes with you? Let's check to see if your instructor did a similar problem in class. Student: Well, I didn't actually attend class this week, and even if I had, I wouldn't have taken notes. TA: Oh dear! You really should go to class! And taking good notes is critical in math classes. Ok then, let's look at the book and see if similar examples are worked there. Student: Hmmm. That looks similar there, doesn't it? TA: Yes. Did you read the chapter before you started trying the problems? Student: No, I can't read the book. It seems too hard. TA: Oh dear! You really need to read the material before starting the homework problems. Read it carefully through even though it might not sink in the first time. The second time you read it, things will start falling in place. Going to class, taking notes, and reading the book are important things you can do to get this course under control. The Math Library is on the floor above. Go there, take a deep breath, and read this chapter, including and especially the worked examples. Then come back and I'll help you. I really can't help you until you have given this material at least a minimum of thought.