Special precautions to ensure safe disposal of sodium-filled exhaust valves
 
The handling and disposal of sodium-filled exhaust valves requires special care and consideration. Under conditions such as breakage with subsequent exposure to water, the sodium metal which lines the inner portion of the exhaust valve will react violently, forming sodium hydroxide and releasing hydrogen gas which may result in an explosion or fire.
•  Damage to eyes may result in loss of vision
•  Contact with skin will result in burns
•  Fire may occur.
 
(1) Basic precautions
•  Never attempt to break valve and remove sodium metal.
•  In principle, dispose of used valves by returning them to the Nissan service office.
•  If valve(s) is/are damaged, remove valve(s), and perform sodium-filled valve disposal operations (neutralization and waste water disposal).

(2) Processing method
In principle, dispose of used valves by returning them to the Nissan service office.
If local industrial waste treatment companies do not perform the required press processing and it is clearly established that a solvent method can be used instead, this type of disposal method is also acceptable, if valve(s) is/are damaged, remove valve(s), neutralize by water reaction and dispose of them with the same method used for ordinary scrap metal.
Processing must be performed as follows.
 
Nissan Skyline GT-R32 Cylinder head ASSY
 
•  Wear rubber gloves to remove valves from cylinder head.
•  Pour more than 10 liters (2-1/4 lmp gal) of water into a bucket in a well-ventilated area.
•  Submerge the damaged valves in the bucket.
•  The reaction is violent so stand 2 to 3 meters (7 to 10 ft) from bucket.
•  Hydrogen gas is produced so do not bring any naked flame near bucket.
•  After the reaction is finished (4-5 hrs.), use large tweezers to pick the valves out. The valves can be disposed of by the same method used for other waste products at this time.
•  Dealers should check their respective state and local regulations concerning any chemical treatment or waste water discharge permits which may be required to dispose of the resultant (high alkalinity) waste water.
CAUTION:
Make sure the resultant (high alkalinity) waste water does not contact your skin. If the waste water does contact the skin, wash the affected area immediately with large quantities of water.