There was a story (I think it was on reddit, not HN) of an entrepreneur who bootstrapped a local cleaning business in something like three months, by hiring his maid as his first employee. The guy does not mop up himself, but runs an incredibly successful business with a web-based reservation system. The rest of his job is people and asset management.

So even with janitorial work, an educated graduate can turn it into a profitable business, without actually doing the cleaning himself.

Edit: his site is http://www.maidsinblack.com/ and he does a great job of documenting his startup experience step by step on reddit. If I find the thread, I'll post it here.