I would put some cautions on the word "safe," regarding d-limonene.  As I
recall, it has a very low flash point (the temperature 117F sticks in my
mind), which makes it a hazardous material.  Also, a fairly large fraction
of the population is allergic to it (or possibly to impurities that are
often not removed from d-limonene-bearing solvents).  I'm one of those
people who are allergic, and I can tell you it's very unpleasant working
with it.  There have also been some toxicological studies that call into
question just how safe it is.

Michael Meltzer


>Ted,
>
>Limonene D is  the d form of limonene which is a monocyclic terpene and was
>originally derived from oil of lemon, orange blossom oils, and oil of
>caraway.  It is used in a wide variety of products   It has a boiling point
>of 177 'C and a mol. wt of 136 and is water insoluble. It is available from
>most chemical supply houses.  Another source is Inland Technology Inc. Tacoma
>Washington  (206) 383-1177, FAX (206) 593-8749, E-mail:
>[log in to unmask]  It is considered a safe (environmental) solvent
>substitute for the the ketones and toluenes as well as TCA.  Presumably meets
>MIL:C-81964A.
>
>Phil Hinton