>> Don't know if this one has been mentioned.
>> I use cement (not premix) and just pour over oil spots and if heavy oil
>> use a good stiff broom to mix in to absorb oil.
My local garage swear by cat litter, it's cheap, adsorbent, and much less of
a heath risk than concrete. I personally have a carpet on my garage floor,
it works grate, when it gets to oily under the engine, I can put sawdust (or
cat litter) on the oil sweep it up then shampoo it! When the carpet is
completely gone it goes to the tip.
It also outdoes the neighbours.
P.S. It's a second hand carpet I found somewhere BTW.