corrsivity of cutting oil

[liveaboard]

I retrieved a motor block from a machine shop yesterday; it was still in the boring / honing machine when I got it, and covered in oily fluid.
The machinist told me something about cleaning and water, but he didn't speak English and I didn't understand more than that.
This morning, there's new rust on the block surface; there could have been condensation in the car overnight.

I cleaned it with paper and wd40, but do I need to get that gunk out of every crevice and oil passage urgently?
I'm going away for a week on Monday and don't want to return to a disaster.

[John Evans]

Never seen any cutting oil that was corrosive ,but they may have been using something water based which can cause surface rust if left on. Especially if not at proper concentration . hose it down good with diesel to wash out passages etc.

[liveaboard]

Thanks; I didn't have the guts to spray diesel around before traveling. That stuff STINKS. But when I get home I'll do it.
The cutting oil looks and smells like a petroleum based product; clear and yellowish. Could be hygroscopic... I guess that would do it.