Anyone know how oil gets on oil cap?

I don't know what the deal is but I look at the oil cap and most of the time it's full of oil, when I say full of oil I mean the concave part of the top of the cap somehow gets oil in it.

I tried replacing the cap think that might help but the new one does it too. The seal around the valve cover is nice and tight so I'm not really sure what's going on here. It's nothing really important but I think it's odd how it's doing that.

Any suggestions?

I believe there is a breather hose in front of the cap. The fan may be blowing oil back. How does the rest of the valve cover look in terms of oil weep?

Looks pretty dry since I replaced the gasket of the valve cover. This seems to be too much oil to be blowing back from the front vent. I'll try to get a pic and post it later

The valve train slings oil around under the valve cover.

Well yeah I know that but how does it get on te to of the oil cap?

If the cap is the only place that oil shows up, then I would look at the underside of the hood. Is your hood liner soaked with oil?