Hey Spinnerkop, from what I read here and from what I see in your replies I can pick up that you really want to use these hides, your questions are directed in such a way that I almost get the idea that you are still questioning the answers you already got. Just a few quick facts on Blue Gum (Eucalyptus)
1. I grew up on a farm with a lot of Eucalyptus trees, nothing else grew
under them as their leaves poisoned the ground and nothing else could
grow there. (This can be confirmed on the internet as normal.) As
children we skipped these trees when we wanted to look for insects and
spiders, we seldom if ever found anything alive close to these trees.
except for the bees coming to the flowers of these trees (Eucalyptus
Honey), nothing else liked these trees very much.
2. The only time they speak about Eucalyptus products in the pet industry
is when they talk about a flea and tick repellent, witch must be
seriously diluted because of the irritation created by the smell of the
Eucalyptus when used on dogs or cats.
3. The last use that I know of for eucalyptus is as a natural SPIDER
CONTROL PRODUCT. Please read the following article
www.howtodothings.com/pets-animals/use-spider-control-products
Eucalyptus is one of the natural products u can use in its raw form to
get rid of unwanted spiders in your home.
So I think it should be clear to you now that you should not try to use Eucalyptus in your T's enclosure, (unless your T is a unwanted spider).
Hope this helps.