On Wed, 5 Sep 2001, Laurie Colbert wrote:
> I'm interested to know what everyone does with their dirty paraffin from
> the tissue processors.  Do you throw it out in the regular trash or do
> you have a hazardous waste company pick it up?

In my lab we process everything by hand these days, but our
paraffin disposal procedure should be OK for larger-scale
operations too.

Start with an empty cardboard box (about a 20 cm cube; could
be bigger). Tape it up if tecessary, then pour used paraffin
slowly round the inside and let it set, to seal any cracks
securely. Add used paraffin from time to time until the box 
is full. Put the solid block in a trash can.

In earlier years we made some of it into candles, with
wax-soaked string for the wicks. Stirring in a pinch of
sudan III, sudan IV or oil red O gave nice red candles.
We don't do this any more because (a) it was quite a lot 
of work, (b) candles are not very expensive and bought
ones look nicer than ones made by untrained amateurs, and 
(c) the electric lights work well nearly all the time and 
there is no real need for a large supply of free candles.

----------------------------------------
John A. Kiernan
Department of Anatomy & Cell Biology
The University of Western Ontario
London,  Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan