Faulty head gasket?

[Raiden]

I went to view a S3 on Sat and it seemed to look in good condition but looking at the oil cap it was a little milky under there. I'm not a mechanic but would that indicate the head gasket has gone? Or if its been sitting about a while could that happen? I said I would think about it. For the asking price he said they would do the cambelt and water pump

 

[Journeyman]

Can be just condensation I have it on Golf, but the head gasket is fine so the garage says

 

[Raiden]

I was hoping that was the case. Not a bad price I thought? http://www.tradelinkcars.co.uk/used-cars/search-results?make=AUDI&model=S3

 

[Mojave96]

If I remember correctly, if that would be the issue, the oil dipstick would have that milky substance on it too.
When I picked up my A3, it had the same thing but it turns out it was condensation. It clears after short time.