Powder Post Beetles

We want to salvage the old growth fir flooring in a 1936 cabin in the Mt Hood area near Portland, Oregon. The cabin is being demolished so we can build a new cabin in the same location.  The cabin is on the Salmon River in Brightwood, Oregon. We want to salvage the flooring to reuse in the new cabin for flooring.  About 1/16 of the boards show powder beetle infestation.  We spotted piles of sawdust in various locations once we pulled up the fir stirps.  The fir is unfinished but dirty from years of wear.  How do I treat the lumber? Does Shellguard kill the beetles?   Do I treat the lumber that shows no sign of infestation too?  I have read that the lumber has to be sanded before a shell guard treatment.  Since the wood doesn’t have a finish, can I only clean the wood with a 10percent bleach solution rather than sand it?
Linda, Portland, Oregon

If the flooring is stored in a very dry location you may have some success spraying the bottom, top and both edges of every plank. Once the planks are re-installed in the new cabin and sanded, you could spray the floor again with a borate solution. The solution may not penetrate deep enough to kill the larva tunnelling through the wood. In Canada, only licensed pest professionals may purchase and apply the most effective borate solution. Adult beetles that emerge from infested wood will not lay eggs on a finished surface. (Varnish, urethane, paint) We are not familiar with the efficacy of Shell-Guard.