I'm sorry but the Foil would have to stay. I'm I got back to work and the desk was covered in Foil, it would be months before it ever came off. Maybe more if they did it right.
I remember in high school I had "gotten" keys to one f my teachers class rooms (good friend teacher not evil ******* teacher), we turned every thin in his room upside down. EVERYTHING even the fire hydrents (engineering classroom) and computers. The desks and even thr trash cans. Even the fixtures where inverted. It took a couple of hours to do and there were 6 of us. He liked to come to class just before it start and when he unlocked the door he nearly fell over. He said he would have gotten us expelled if it wern't for the fact the we did such a complete job and demonstrated an ability to work as a team and over come many enginering problems (inverting electrical stuff in a manor that did not violate any building codes or cause problems and such) Of course he only gave us such complements after calling us all in after school and handing us all upside down referals LOL. I think the fire extinguisher plaques are still upside down to this day. He was inverting stuff for months. Every time he would have to stop and laugh, (like when he would go to put the marker down on the dry erase board and notice the trough for it was at the top)