My chain and cogs always look very dirty as the oil attracts dirt. It is a constant problem as you can't fully avoid stains on your trousers and hands. Also, that looks ugly and I believe it wears the chain and the cassette out as the particles stuck on chain act as abrasive.
I used to think that was unavoidable, but then I noticed that on some bikes the chain and cogs are shiny clean. Is that because their owners clean the chain daily (because honestly one day is enough for a chain to turn black after full cleaning) or because they use different lubrication solutions?
I heard about teflon-based lubricants, are they really much better in that sense than traditional oil-based ones? Also, these bikes with shiny chains were always single-speed bikes - does that mean geared system experience more traction and should be traditionally oiled?