My understanding, and the practice I follow, is to wipe any of the external surfaces. It is the lubrication on the roller pins that protects the chain.

This is toward the end of a 3,000 mile tour, with about 400 miles on dirt and gravel, and 35 days of rain. I used the lube and wipe method, and the chain is still reasonably clean. I would have cleaned the rear derailleur, but we only had a few days left to ride. The grass was just picked up that day--my wife took a shortcut


I usually put a new chain on prior to a tour, and check it on returning home. This particular chain needed replacing. Depending on conditions we get 3,000 to 4,000 miles from a chain.