Treated lumber and scraps can be disposed of in the trash. Treated wood should never be burned in a fireplace or campfire because of the chemicals it contains.
These procedures are intended for small quantities of wood preservatives from a household only.
Disposal of untreated lumber:
Conduct activities outdoors or provide adequate ventilation by opening windows and doors and/or turning on a room fan. Stay away from potential ignition sources like pilot lights or sparks of any kind.
Protective clothing such as chemical resistant gloves, eye protection and long sleeves should be worn, and care should be taken not to breathe any fumes.
For small quantities, apply the unwanted wood preservative to scrap wood or cardboard outside in a well ventilated area away from potential ignition sources, children and pets. Allow it to dry, then put the material in the trash.
For larger quantities, mix the wood preservative with kitty litter or other clay-based absorbent in a plastic tray or bucket until the absorbent is moist, but not dripping.
Set the mixture outside in a well-ventilated area away from potential ignition sources, children and pets. Allow to dry. If you have additional liquid, this procedure can be repeated using the dried absorbent.
Wrap the dried absorbent in a trash bag and put it in the trash.
Empty product cans can also be placed in the trash. Leave the lids off of the cans so that your trash hauler can tell they are empty and/or dried.