Back in the 1960s 70% alcohol was the "safe" holding
medium, and for dehydrated and cleared objects, you
put them in melted wax and let the wax solidify.

Having followed these principles and frequently
varied them, by mistake and for convenience, I can
offer some experience-based advice (wholly anecdotal; 
no controlled studies). 70% alcohol is OK, and
so are the more viscous clearing agents, notably
terpineol and cedarwood oil. A few days in molten
wax probably does no harm to specimens that have been
completely dehydrated and adequately cleared of
alcohol. With manual processing it is easy to be
sure that nearly all the water and nearly all the
alcohol have been removed. With a processing machine
there is necessarily much uncertainty, so 70% alcohol 
is probably the best option for a holding medium.
-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/