I snagged some beautiful and massive pieces of rhododendron wood off of a long dead plant. It’s bone dry through and through, but still kept some bark which is cool. I am very aware living rhodies contain grayanotoxins which can be fatal to animals (including humans). Logically it seems like it would be safe once it’s long dead, if it isn’t producing anything else how would it produce poison? If it’s very dry, boiled, and soaked for a long time, it safe to use in a tank?