The message
from "Ray Warner" contains these words:

Has anyone come across instructions for drying blueberries (and cranberries
for the matter)

Also I want to get hold of a good field guide to funghi, with illustrations
and detailed descriptions etc (no sense in killing myself with my first
gatherings). Any suggestions folks?

Others adequately have dealt with the mushroomy bit.

You can dehydrate things by putting them in a net or on a non-corrodible
mesh in a closed container over calcium chloride crystals.

These are available from some hardware shops as refills for moisture-traps.

Water absorbed by the crystals can be driven off later by heating the
crystals (or the fluid, if a lot has been absorbed.)

--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/