Before my engine was rebuilt, there was always an accumulation of oil sitting in the bottom of the air filter canister and in the creases in the connecting hose. Since the rebuild, the canister and hose seem to stay dry/clean - so the oil in your case may be attributable to a worn engine as well. After all, the oil that leaked out of the hose on your car has nowhere else to go but the bottom of the canister once you put the requisite clamp in place, and it will not do much good there :evil: !
Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic