They were given to my 8th grade math students, which was even more effective b/c with around 100 students, they obviously don't all get to test with me. I thought some might find it cheesy, but even my toughest students wanted one and held on to it.
After test scores came back a few students who had never passed before, finally did, and attributed it to their lucky pencil! Since then, I have continued the tradition.I purchased mine from Oriental Trading costing $17 for 72 pencils. Let me know if you find them somewhere else for less.