What does "cleaned for PREMIX" mean?
There are several versions of a dive tank VIP decal for sport Nitrox & Oxygen service that is widely available to anyone who wishes to purchase them online from Amazon and eBay. They typically have a punch out described as "cleaned for PREMIX oxygen content 22% to 40%". We will be blunt and clearly state these decals are meaningless; they have no provenance and reference no standards as well as being dangerously inaccurate. Local dive shops following best practice will not normally honor this type of VIP decal.
In rare cases, a shop will insist on some form of after-market "cleaning" before agreeing to fill a tank not sold by them. They have that right, but we want you to know that no such service can make a new empty cylinder and valve marked Nitrox Ready from Dive Gear Express any more oxygen clean.