Cleaning the chip on cards can eliminate errors.
We used to keep a small bottle of rubbing alcohol to wipe the chip clean, but we now have some packaged "wipes" that I got from Mike at the TCard Office.
I keep a supply of these in the Infodesk printer cabinet. (lower shelf on the left)
They are about 1" square in size.
They are to be used by staff at either of our public service desks, so please help yourself when needed. And let me know if you think we need more.
If there are no wipes available, the old trick of using some cotton fabric to clean the chip is also useful.