Old visiting cards as bookmarks!

What do you do with your old visiting cards when there is change in particulars like telephone numbers and email IDs?

I made use of the picture from my book "Babloo goes for an eye test", and along with the tag "I care for eye care", affixed it on the front side of obsolete cards...to be given away to children and older adults as bookmarks!

Dr. Narendra Kumar
Ophthacare Eye Centre
C4F/216 Janakpuri, New Delhi 110058
Phone No.011-25599839, ophthacare@gmail.com