An old preservative that's been rediscovered. Nontoxic to humans and animals, borates also increase wood's fire resistance.
Borates treated wood is unchanged in color also protects from wood eating insects and most fungi.
Spray application is used for treating wood in place. Today, borate's biggest use is in treating timbers for log structures and post and beam construction. The stumbling block is that Borate remains water soluble and leach out of treated wood that gets wet. Leaching from the exterior log walls is all but eliminated by applying a water repellent sealer . Twist the three pipe cleaners in the middle so that you have a six sided star.