My house has finished concrete floors. My husband had put a chainsaw on the floor and it made an oil stain that I haven't been able to get up. What can I use to get the oil stain out?
I'm not sure how applicable this solution is to finished concrete (It depends on how polished your floor is I suppose), but an old solution can be found in this video.
Essentially, you take oil dry and spread it out over the stain, then you start to grind the absorbent into the concrete. In the video the guy used a brick, but I've always just put on my mowing shoes and went to town with my legs. In hindsight, brick sounds easier, but then again, it may depend on how polished your floors are.
If you know someone working at a gaz station you could ask them some of their absorbent. You might also find this sort of thing in hardware shops... I always found it looked it paperish sand. This will suck up most of the spill in no time. Once you have have removed everything (do not use a vacuum, this could set it on fire), use dish soap to clean the rest.