Removing tannin to make oak safe

[Merrick]

So for those of you who want to make natural tree limb perches but don't have access to a wide range of tree species oak maybe your only option. Some oaks are better than others like cork oak but most have high tannin levels which are dangerous to our parrot companions. So one way to remove tannins is to boil the wood.
What I do is find a pot that fits the size of the branch (which greatly limits my selection of different size branches )
Then I put the branch in with water to completely surround it
Then bring to a boil, let boil for 15 min
Repeat until water no longer turns brown