One of our researchers submitted a project to our lab that had been
labeled by one of his assistants with a lab pen.  After processing, the 
cassettes were completely void of any identification.  This experiment 
was lost and after the pen/pencil discussion some months back on Histonet  
I decided to see if I could come up with the ideal means of marking slides and
cassettes, at least for our researchers in this lab.  We use the Cassmark
2 to label our cassettes and are currently using the Securline pen for
cassettes so this was just for our research departments. 

I gathered each pencil and marking type pen that I could find in this
department.   I labeled one slide and one cassette with each pencil and
pen. I ran the cassettes in the VIP with the next days surgicals and ran
the slides through the Sakura stainer also with the surgicals.

The results were:

The ONLY pen that did not make it was the Sharpie.  It did not
withstand the processor nor did it make it through the staining.  It came
off of the  cassette and the slide. The three top pen winners were the
Shurmark, Paper Mate and Securline.

The top pencil winners were disposables by Paper Mate and Dixon Yellow.
The Schwan, and the Tissue Tek both did an excellen job.  Every pencil I
tested worked very well on both slides and cassettes with the exception of
2 very old #2's.

I tested 6 pens and 14 pencils, must have been a slow day.

Cel Rutledge
San Francisco General Hospital
San Francisco, Cal.