I just want to clear up any misconceptions about how a chain works. This picture is from
RK chains
The O, X & W... sealed chains have grease in them to lubricate between the Pin and bushing, which move relative to each other as the chain goes into and out of mesh at the sprockets.
The grease also lubricates the O-ring (seal) as the inner and outer plates also move relative to each other. The seals job is to retain the tiny amount grease.
The final moving part is the roller that wraps around the bushing. It turns relative to the bushing when the chain goes in and out of mesh with the sprockets and has NO trapped lubricant. This is where chain lubricant comes in. It needs to be an oil or solid lubricant of some kind that is compatible with the O-ring and can penetrate into the tiny gap.
A word about the seal. RK states that the seal is Nitrile Butadiene. A widely used seal material and is therefore relatively cheap. It is good, but not the best, so treat it kindly. Keep grunge brushes away from it, the hairs can slide between the side plates and o-ring and damage the seal. Might even let out some of the trapped grease and push in particles of sand/grit.
ME? I never clean them, only lube them.
Best lube method is a totally enclosed chain dipping into a bath of oil.
Next best is one that supplies a small amount of oil on a continuous basis, when moving.
Next best, chain lube.
Worst - nothing
Next worse - nothing plus cleaning