lol i was imagining a load of black gunk.... just wipe it a kitchen towel, put it back and leave it.
There looks to be excessive oil on the filter, but not much. The oil is meant to be there as it collects the particles. There's a special filtration system on them that allows the engine to breath still.
Just received this from itg .The Pro-Filter is supplied oiled with a Silkolene product which is green in colour. If the filter is dry the dust particles have nothing to stick to and so work their way through the filter and into the engine.
The only way I could imagine that the oil could get that brown colour is if it was very dirty or if there was dirty water getting into the air box.
Our technical sales manager is back in tomorrow so I will discuss it with him and our Engineering Director.