Why would you pour orange on your hat?

At the weekend I saw an odd thing. In the shopping centre, a tramp was pouring orange onto his hat.

He was, without being too facetious, your classic tramp. At least seven layers of clothing, ruddy, weathered face and wild beard containing remnant food. So far, so trampish.

In his chunky hands he had a flat cap, onto the outer edge of which he was carefully and meticulously pouring small quantities of orange juice from a plastic bottle. I know it was orange juice as the bottle was one of those small Tropicana ones they sell in McDonalds to entertain a veneer of health over their mostly fat and salt saturated products. It could have been piss, I suppose, but it looked like orange juice. I wasn't going to lean over and sniff. Besides, wondering why someone might be pouring piss over their hat rather than orange juice opens up a whole raft of other questions about tramps. I don't want to go into those right now.

But why would you carefully pour orange juice over your hat?

All I can think of is a: cooling, b: fragrance or c: some form of pest control. Any other suggestions will be gratefully recieved.