[2111USMC]

I know this is a pretty far-fetched possibility. But what if it was some Park Service guy with a weed-whacker spraying oil out of it as he trimmed the grass along the walk?

(Although this wouldn’t explain the comments by “SDS” posted earlier.)

[pillut48]

That kind of oil is darker and more viscous usually, isn’t it?
(Thank you for the opportunity to use the word ‘viscous’, I don’t get to do that much!)