Re: Xylene usage

From:David & Marjorie Cardwell <>

Back in the mid eighties I attended a course in England (at Miles, I think)
teaching how to service the VIP. (This was offered as an alternative to a
free one-year service contract, I seem to recall.)

The chap who gave the talks said that they had run two VIPs side by side for
6 months They changed the reagents frequently in one, and never changed the
other's. He said that after six months the unchanged reagents were
completely black, but there was no discernible difference in the cutting or
staining properties of the tissue!

This confirmed a long held suspicion of mine, based on the simple
mathematics of the situation. Say for the sake of argument you have three
one-litre alcohol baths in a processor, and 1 ml/l of water is carried over
into the first alcohol. The second will receive 1 microlitre of water, and
the third will be contaminated by a mere 1 nanolitre! Pretty much
negligible, I would say. And imagine how little water will be present in the
last xylene of the typical processor.

Ever since then I have winced at the amount of unnecessary waste I have
witnessed, but it's very hard to convince people that they can get away with
much less frequent changing of reagents.

- David Cardwell, Frankston, Australia

From: "Jeff Silverman" <>

Here's a subject dear to my heart.I'm one of those histotechs who tries to
get the most mileage out of my solutions. By close monitoring of microtomy
and staining characteristics, I have found that it is not at all detrimental
to use the same two baths of xylene for up to four weeks, 5 days per week.
Over twenty years I have done this stretching act on a Technicon duo, later
on a VIP, and most recently on a Shandon Path Centre for up to four weeks
processing 40-90 blocks per day including numerous breast and skin
specimens. Even though the solutions get quite yellow, they function very
well for three and sometimes up to four weeks as long as absolutes and
paraffins are rotated weekly, or maybe after a week and a half. If you are
careful and observant, it really is possible to stretch out the useful life
of xylenes. My xylene waste per month is just under two gallons (7500
surgicals/year). We use limonene to purge and stain. Just my experience.

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