Keyboard Stickers Keep Slip, Slip, Slippin' Away

After weeks of forgetting I finally remembered to send stickers for a student's word processor out to the school.  The student has hemianopsia and has a great deal of difficulty locating the keys on her portable keyboard.  She is able to locate letters with less difficulty if she uses an Intellitools keyboard connected to a computer, but sometimes she needs something more portable.
Alas, the teacher told me that the stickers worked well at first but they began slipping off the keys upon the slightest touch.  Not good.  I should have cleaned the keys with rubbing alcohol prior to applying the stickers, to remove the oils left behind by all of our fingertips.
So, I removed the stickers today, wiped down the keys with rubbing alcohol, and reapplied the same stickers.  Might have to bring in brand new stickers if the old ones don't stay firmly attached, but we'll try the old ones and see how it goes.