Clean equipment that comes into contact with oxygen requires specific procedures to ensure that nothing is left on the surface that could interact with oxygen. There are two types of cleaning that are pertinent for oxygen equipment, cleaning with oxygen compatible cleaners and cleaning equipment for oxygen service.

1. Cleaning With Oxygen Compatible Cleaners
Oxygen can react with any residue, particles, dirt, oil, grease or other contaminants that are left on the surface of equipment that comes into contact with oxygen, such as the cylinder surface. The body of a cylinder, or a regulator for example, should be cleaned with chemicals that will leave nothing behind to cause an interaction with oxygen.

2. Cleaning Equipment For Oxygen Service
Surfaces that come into direct contact with oxygen, such as the valve opening on a cylinder, the inside of a cylinder or oxygen connection, must not only be cleaned with an oxygen compatible cleaner, but also with special equipment and processes to ensure that the surface has no particles left behind. If there are even small particles on the wetted surface, the speed of the oxygen coming out of the valve, could actually ignite the particles. 
The procedure you’ll have to follow for this is found in CGA G 4.1.