Magnetic nail polish

Perhaps this could be sub-titled "An old man makes a fool of himself"??  My Physics teachers's email network alerted me to magnetic nail polish. You apply it and whilst it is wet you hold the cap of the bottle over your finger nail. The cap contains a patterned magnet which pulls iron filings (one person suggested cobalt, which is also magnetic) into the pattern of the magnets.  I had a great time swanning around with it on at school...