Dear C Jones,

Is it possible your absolute ethanol is not absolutely absolute?

I have had absolute alcohol that was more like 95 - 98%. Is there any sign
of 

water in the first xylene station?

We have 2 Leica TP1050's and have not had a carry-over problem, or any

other processing problems.

Did the service people check and clean the selector plate/ manifold plate

in the rotary valve assembly? I have heard that it is possible for things
like

formalin salts to build up and cause small contamination type faults.

Hope you find the cause, David.

David Taylor
Laboratory Manager
Drs King & Mower
Adelaide, Australia