Today you can get copper naphthalene pretty easily and use that. I believe that’s probably what you’re seeing at the home improvement stores. It is green. You will have some tell you it promotes nail/screw sickness but we are only using a top coat, not a pressure type process. The research I did on my 32’ Olds (which I used the copper naphthalene, and had some tell me I was wrong!) showed the factory used copper arsenic which of course is no longer available and if cutting old would framing to splice in new pieces, one should use a canister respirator for caution. What’s crazy is the copper naphthalene is also used on the soles of horses feet to treat thrush or rotting of the sole/frog of the hoof.