Make ornament aquarium safe

[neon1423]

Hey all, so cliffs notes story, my mother has a beech themed tank and has looked forever trying to find a lawn chair to put in the tnak. I managed to find a small chair on a minatures website http://www.miniatures.com/Unfinished-Mini-Adirondack-Chair-P26797.aspx
The site says its made of wood but I wouldnt trust puting it straight into the aquarium. Is there a way of making this safe for the aquarium?