Apple wood is commonly sold with the belief that it will be used for cooking or in a fireplace. The result is the starter pieces are branches of fair size, like 2" (50mm) diameter and larger.
IMHO, Apple wood is to be used around Parrots with caution. Apple trees are attacked by so many different bugs, etc... that they are sprayed a minimum of two time during the grow season. Although, the chemicals are all water based these days, the regular exposure to spraying should set in the back of ones mind.
For me to use Applewood, I would (as noted above) Hot water wash them (I like Dawn Original) and fresh water (drinking quality) rinsed. And that would be done after debarking the branches! AS AN FYI: The bark is that part that is most exposed to the environment and if there is stuff to be concerned with it would be in the bark.
Heating Wood: There are several opinions regarding what assure a safe product for your Parrots.
- IMHO, the placement in Bright Sunlight for several hours is the best for killing-off whatever remains. Clearly turning often during that period.
- Heating Wood: Here, I have concerns regarding the temperature as Wood 'can' localize heat to a higher temperature than that of a temperature control device. Example: A thin edge /slice of wood can flame at temperature around 270 degrees F whereas the body of the branch is barely 140 degrees F. The question is what is one hoping that heating will accomplish? If the wood is buggy, you will see it while debarking and bypass that piece for use with your Parrot. The washing would have removed the chemicals. Understanding that heating is commonly used to drive moisture out of the wood.