[Histonet] labeling pre-made slides

[Hutton, Allison]

We use the Leica IPS to label our cytology slides, however, we do get quite a few slides from doctors who make smears and spray fix them before they come to us.  Unfortunately, they use pencil to label and this usually wipes off during staining and coverslipping.  Does anyone else receives slides like this and then how are they permanently labeled?  We would like to avoid going back to paper labels if at all possible.
Any advice or suggestion is appreciated
Thanks
Allison