Hi Lisa,
If the students just went in beside the vein and the fluid did not enter the arm itself, you can tie the arm up by the hand to an IV pole to allow drainage for a day or two. This is very effective.
If they did enter the foam of the arm itself, remove the arm and roll the skin back on itself, then lay the arm down on some towels or other absorbent material. Cover with more absorbent material and step carefully from the hand to the upper arm to remove the extra fluid. Then hang the arm from the IV pole as described above for a day or two. Using a hand held hair dryer, warm the arm skin up to assist in rolling it back up the arm.
This is a two person job, one to hold the hand and dryer, the other to slip the skin up. Be careful not to tear the skin. It does take a little time but is very worth doing so you don't have mold in the arm.
Have fun!
Dani