The basic procedure is as follows:
- Dissect the majority of the internal organs, being careful not to scrape the cuticle as the outer layers are transparent.
- Dust the inside with Borax crystals and stuff with cotton wool to retain shape.
Judith Marshall offered some pointers to do with the dissection:
As well as some changes to the method suggested by Rentz:
So there you go - hopefully of use to somebody.
There are also methods involving the use of 'embalming' fluids - which are pretty nasty cocktails of chemicals and probably best avoided.