You can also find materials in the hardware store made for it.

That's what I was wondering. I don't recall ever seeing concrete cleaners
in the stores. Any stores or brands you would suggest?

I use kitty litter to soak up as much as possible

Yep, same here, as soon as I possibly can after the spill occurs.

On some of the bad spots, I'll spray on a generic degreaser and cover with
kitty litter again. Usually gets the worst out.

I've also found that the fine saw dust from my woodworking helps soak up a
little bit too.

it's time to deal with the cause of the oil stains

We don't park our cars in the garage unless I'm working on them, which
lately has been to fix some annoying leaks. Unfortunately, it's not
always possible to get a drip pan under the item that is leaking (like the
power steering hoses I just replaced). And then there's always the
unplanned "surprise" spills. So a few spills are unavoidable. I try to put
a sheet of cardboard or something down if I anticipate a messy job, but
again, some spills aren't planned...

Anthony