Final answer:
Smoke stains on unfinished wood can be treated with oxalic acid, a strong chemical requiring careful handling and proper safety gear during use.
Step-by-step explanation:
Remaining smoke stains on unfinished wood might be removed with a procedure using oxalic acid, which is considered to be a salvage procedure when dealing with wood that has been stained. It is important to handle oxalic acid with care, as it is a strong chemical that can be harmful if not used properly. If you decide to use oxalic acid, make sure to wear protective gear such as gloves and safety glasses, and follow the instructions carefully to ensure the safety and effectiveness of the wood treatment.